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Version: 0.9

DataFusion Functions

This page is generated from the Apache DataFusion project's documents:

Scalar Functions​

Math Functions​

abs​

Returns the absolute value of a number.

abs(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
acos​

Returns the arc cosine or inverse cosine of a number.

acos(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
acosh​

Returns the area hyperbolic cosine or inverse hyperbolic cosine of a number.

acosh(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
asin​

Returns the arc sine or inverse sine of a number.

asin(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
asinh​

Returns the area hyperbolic sine or inverse hyperbolic sine of a number.

asinh(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
atan​

Returns the arc tangent or inverse tangent of a number.

atan(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
atanh​

Returns the area hyperbolic tangent or inverse hyperbolic tangent of a number.

atanh(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
atan2​

Returns the arc tangent or inverse tangent of expression_y / expression_x.

atan2(expression_y, expression_x)
Arguments​
  • expression_y: First numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression_x: Second numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
cbrt​

Returns the cube root of a number.

cbrt(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
ceil​

Returns the nearest integer greater than or equal to a number.

ceil(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
cos​

Returns the cosine of a number.

cos(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
cosh​

Returns the hyperbolic cosine of a number.

cosh(numeric_expression)
degrees​

Converts radians to degrees.

degrees(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
exp​

Returns the base-e exponential of a number.

exp(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to use as the exponent. Can be a constant, column, or function, and any combination of arithmetic operators.
factorial​

Factorial. Returns 1 if value is less than 2.

factorial(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
floor​

Returns the nearest integer less than or equal to a number.

floor(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
gcd​

Returns the greatest common divisor of expression_x and expression_y. Returns 0 if both inputs are zero.

gcd(expression_x, expression_y)
Arguments​
  • expression_x: First numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression_y: Second numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
isnan​

Returns true if a given number is +NaN or -NaN otherwise returns false.

isnan(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
iszero​

Returns true if a given number is +0.0 or -0.0 otherwise returns false.

iszero(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
lcm​

Returns the least common multiple of expression_x and expression_y. Returns 0 if either input is zero.

lcm(expression_x, expression_y)
Arguments​
  • expression_x: First numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression_y: Second numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
ln​

Returns the natural logarithm of a number.

ln(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
log​

Returns the base-x logarithm of a number. Can either provide a specified base, or if omitted then takes the base-10 of a number.

log(base, numeric_expression)
log(numeric_expression)
Arguments​
  • base: Base numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
log10​

Returns the base-10 logarithm of a number.

log10(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
log2​

Returns the base-2 logarithm of a number.

log2(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
nanvl​

Returns the first argument if it's not NaN. Returns the second argument otherwise.

nanvl(expression_x, expression_y)
Arguments​
  • expression_x: Numeric expression to return if it's not NaN. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression_y: Numeric expression to return if the first expression is NaN. Can be a constant, column, or function, and any combination of arithmetic operators.
pi​

Returns an approximate value of π.

pi()
power​

Returns a base expression raised to the power of an exponent.

power(base, exponent)
Arguments​
  • base: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • exponent: Exponent numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
Aliases​
  • pow
pow​

Alias of power.

radians​

Converts degrees to radians.

radians(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
random​

Returns a random float value in the range [0, 1). The random seed is unique to each row.

random()
round​

Rounds a number to the nearest integer.

round(numeric_expression[, decimal_places])
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • decimal_places: Optional. The number of decimal places to round to. Defaults to 0.
signum​

Returns the sign of a number. Negative numbers return -1. Zero and positive numbers return 1.

signum(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
sin​

Returns the sine of a number.

sin(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
sinh​

Returns the hyperbolic sine of a number.

sinh(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
sqrt​

Returns the square root of a number.

sqrt(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
tan​

Returns the tangent of a number.

tan(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
tanh​

Returns the hyperbolic tangent of a number.

tanh(numeric_expression)
Arguments​
  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
trunc​

Truncates a number to a whole number or truncated to the specified decimal places.

trunc(numeric_expression[, decimal_places])
Arguments​

  • numeric_expression: Numeric expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.

  • decimal_places: Optional. The number of decimal places to truncate to. Defaults to 0 (truncate to a whole number). If decimal_places is a positive integer, truncates digits to the right of the decimal point. If decimal_places is a negative integer, replaces digits to the left of the decimal point with 0.

Conditional Functions​

coalesce​

Returns the first of its arguments that is not null. Returns null if all arguments are null. This function is often used to substitute a default value for null values.

coalesce(expression1[, ..., expression_n])
Arguments​
  • expression1, expression_n: Expression to use if previous expressions are null. Can be a constant, column, or function, and any combination of arithmetic operators. Pass as many expression arguments as necessary.
nullif​

Returns null if expression1 equals expression2; otherwise it returns expression1. This can be used to perform the inverse operation of coalesce.

nullif(expression1, expression2)
Arguments​
  • expression1: Expression to compare and return if equal to expression2. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression2: Expression to compare to expression1. Can be a constant, column, or function, and any combination of arithmetic operators.
nvl​

Returns expression2 if expression1 is NULL; otherwise it returns expression1.

nvl(expression1, expression2)
Arguments​
  • expression1: return if expression1 not is NULL. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression2: return if expression1 is NULL. Can be a constant, column, or function, and any combination of arithmetic operators.
nvl2​

Returns expression2 if expression1 is not NULL; otherwise it returns expression3.

nvl2(expression1, expression2, expression3)
Arguments​
  • expression1: conditional expression. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression2: return if expression1 is not NULL. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression3: return if expression1 is NULL. Can be a constant, column, or function, and any combination of arithmetic operators.
ifnull​

Alias of nvl.

String Functions​

ascii​

Returns the ASCII value of the first character in a string.

ascii(str)
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.

Related functions: chr

bit_length​

Returns the bit length of a string.

bit_length(str)
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.

Related functions: length, octet_length

btrim​

Trims the specified trim string from the start and end of a string. If no trim string is provided, all whitespace is removed from the start and end of the input string.

btrim(str[, trim_str])
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • trim_str: String expression to trim from the beginning and end of the input string. Can be a constant, column, or function, and any combination of arithmetic operators. Default is whitespace characters.

Related functions: ltrim, rtrim

Aliases​
  • trim
char_length​

Alias of length.

character_length​

Alias of length.

concat​

Concatenates multiple strings together.

concat(str[, ..., str_n])
Arguments​
  • str: String expression to concatenate. Can be a constant, column, or function, and any combination of string operators.
  • str_n: Subsequent string column or literal string to concatenate.

Related functions: concat_ws

concat_ws​

Concatenates multiple strings together with a specified separator.

concat(separator, str[, ..., str_n])
Arguments​
  • separator: Separator to insert between concatenated strings.
  • str: String expression to concatenate. Can be a constant, column, or function, and any combination of string operators.
  • str_n: Subsequent string column or literal string to concatenate.

Related functions: concat

chr​

Returns the character with the specified ASCII or Unicode code value.

chr(expression)
Arguments​
  • expression: Expression containing the ASCII or Unicode code value to operate on. Can be a constant, column, or function, and any combination of arithmetic or string operators.

Related functions: ascii

ends_with​

Tests if a string ends with a substring.

ends_with(str, substr)
Arguments​
  • str: String expression to test. Can be a constant, column, or function, and any combination of string operators.
  • substr: Substring to test for.
initcap​

Capitalizes the first character in each word in the input string. Words are delimited by non-alphanumeric characters.

initcap(str)
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.

Related functions: lower, upper

instr​

Alias of strpos.

Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • substr: Substring expression to search for. Can be a constant, column, or function, and any combination of string operators.
left​

Returns a specified number of characters from the left side of a string.

left(str, n)
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • n: Number of characters to return.

Related functions: right

length​

Returns the number of characters in a string.

length(str)
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
Aliases​
  • char_length
  • character_length

Related functions: bit_length, octet_length

lower​

Converts a string to lower-case.

lower(str)
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.

Related functions: initcap, upper

lpad​

Pads the left side of a string with another string to a specified string length.

lpad(str, n[, padding_str])
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • n: String length to pad to.
  • padding_str: String expression to pad with. Can be a constant, column, or function, and any combination of string operators. Default is a space.

Related functions: rpad

ltrim​

Trims the specified trim string from the beginning of a string. If no trim string is provided, all whitespace is removed from the start of the input string.

ltrim(str[, trim_str])
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • trim_str: String expression to trim from the beginning of the input string. Can be a constant, column, or function, and any combination of arithmetic operators. Default is whitespace characters.

Related functions: btrim, rtrim

octet_length​

Returns the length of a string in bytes.

octet_length(str)
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.

Related functions: bit_length, length

repeat​

Returns a string with an input string repeated a specified number.

repeat(str, n)
Arguments​
  • str: String expression to repeat. Can be a constant, column, or function, and any combination of string operators.
  • n: Number of times to repeat the input string.
replace​

Replaces all occurrences of a specified substring in a string with a new substring.

replace(str, substr, replacement)
Arguments​
  • str: String expression to repeat. Can be a constant, column, or function, and any combination of string operators.
  • substr: Substring expression to replace in the input string. Can be a constant, column, or function, and any combination of string operators.
  • replacement: Replacement substring expression. Can be a constant, column, or function, and any combination of string operators.
reverse​

Reverses the character order of a string.

reverse(str)
Arguments​
  • str: String expression to repeat. Can be a constant, column, or function, and any combination of string operators.

Returns a specified number of characters from the right side of a string.

right(str, n)
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • n: Number of characters to return.

Related functions: left

rpad​

Pads the right side of a string with another string to a specified string length.

rpad(str, n[, padding_str])
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • n: String length to pad to.
  • padding_str: String expression to pad with. Can be a constant, column, or function, and any combination of string operators. Default is a space.

Related functions: lpad

rtrim​

Trims the specified trim string from the end of a string. If no trim string is provided, all whitespace is removed from the end of the input string.

rtrim(str[, trim_str])
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • trim_str: String expression to trim from the end of the input string. Can be a constant, column, or function, and any combination of arithmetic operators. Default is whitespace characters.

Related functions: btrim, ltrim

split_part​

Splits a string based on a specified delimiter and returns the substring in the specified position.

split_part(str, delimiter, pos)
Arguments​
  • str: String expression to spit. Can be a constant, column, or function, and any combination of string operators.
  • delimiter: String or character to split on.
  • pos: Position of the part to return.
starts_with​

Tests if a string starts with a substring.

starts_with(str, substr)
Arguments​
  • str: String expression to test. Can be a constant, column, or function, and any combination of string operators.
  • substr: Substring to test for.
strpos​

Returns the starting position of a specified substring in a string. Positions begin at 1. If the substring does not exist in the string, the function returns 0.

strpos(str, substr)
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • substr: Substring expression to search for. Can be a constant, column, or function, and any combination of string operators.
Aliases​
  • instr
substr​

Extracts a substring of a specified number of characters from a specific starting position in a string.

substr(str, start_pos[, length])
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • start_pos: Character position to start the substring at. The first character in the string has a position of 1.
  • length: Number of characters to extract. If not specified, returns the rest of the string after the start position.
Aliases​
  • substring
substring​

Alias of substr.

translate​

Translates characters in a string to specified translation characters.

translate(str, chars, translation)
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • chars: Characters to translate.
  • translation: Translation characters. Translation characters replace only characters at the same position in the chars string.
to_hex​

Converts an integer to a hexadecimal string.

to_hex(int)
Arguments​
  • int: Integer expression to convert. Can be a constant, column, or function, and any combination of arithmetic operators.
trim​

Alias of btrim.

upper​

Converts a string to upper-case.

upper(str)
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.

Related functions: initcap, lower

uuid​

Returns UUID v4 string value which is unique per row.

uuid()
overlay​

Returns the string which is replaced by another string from the specified position and specified count length. For example, overlay('Txxxxas' placing 'hom' from 2 for 4) → Thomas

overlay(str PLACING substr FROM pos [FOR count])
Arguments​
  • str: String expression to operate on.
  • substr: the string to replace part of str.
  • pos: the start position to replace of str.
  • count: the count of characters to be replaced from start position of str. If not specified, will use substr length instead.
levenshtein​

Returns the Levenshtein distance between the two given strings. For example, levenshtein('kitten', 'sitting') = 3

levenshtein(str1, str2)
Arguments​
  • str1: String expression to compute Levenshtein distance with str2.
  • str2: String expression to compute Levenshtein distance with str1.
substr_index​

Returns the substring from str before count occurrences of the delimiter delim. If count is positive, everything to the left of the final delimiter (counting from the left) is returned. If count is negative, everything to the right of the final delimiter (counting from the right) is returned. For example, substr_index('www.apache.org', '.', 1) = www, substr_index('www.apache.org', '.', -1) = org

substr_index(str, delim, count)
Arguments​
  • str: String expression to operate on.
  • delim: the string to find in str to split str.
  • count: The number of times to search for the delimiter. Can be both a positive or negative number.
find_in_set​

Returns a value in the range of 1 to N if the string str is in the string list strlist consisting of N substrings. For example, find_in_set('b', 'a,b,c,d') = 2

find_in_set(str, strlist)
Arguments​
  • str: String expression to find in strlist.
  • strlist: A string list is a string composed of substrings separated by , characters.

Binary String Functions​

encode​

Encode binary data into a textual representation.

encode(expression, format)
Arguments​

  • expression: Expression containing string or binary data

  • format: Supported formats are: base64, hex

Related functions: decode

decode​

Decode binary data from textual representation in string.

decode(expression, format)
Arguments​

  • expression: Expression containing encoded string data

  • format: Same arguments as encode

Related functions: encode

Regular Expression Functions​

Apache DataFusion uses a PCRE-like regular expression syntax (minus support for several features including look-around and backreferences). The following regular expression functions are supported:

regexp_like​

Returns true if a regular expression has at least one match in a string, false otherwise.

regexp_like(str, regexp[, flags])
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • regexp: Regular expression to test against the string expression. Can be a constant, column, or function.
  • flags: Optional regular expression flags that control the behavior of the regular expression. The following flags are supported:
    • i: case-insensitive: letters match both upper and lower case
    • m: multi-line mode: ^ and $ match begin/end of line
    • s: allow . to match \n
    • R: enables CRLF mode: when multi-line mode is enabled, \r\n is used
    • U: swap the meaning of x* and x*?
Example​
select regexp_like('Köln', '[a-zA-Z]ö[a-zA-Z]{2}');
+--------------------------------------------------------+
| regexp_like(Utf8("Köln"),Utf8("[a-zA-Z]ö[a-zA-Z]{2}")) |
+--------------------------------------------------------+
| true                                                   |
+--------------------------------------------------------+
SELECT regexp_like('aBc', '(b|d)', 'i');
+--------------------------------------------------+
| regexp_like(Utf8("aBc"),Utf8("(b|d)"),Utf8("i")) |
+--------------------------------------------------+
| true                                             |
+--------------------------------------------------+

Additional examples can be found here

regexp_match​

Returns a list of regular expression matches in a string.

regexp_match(str, regexp[, flags])
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • regexp: Regular expression to match against. Can be a constant, column, or function.
  • flags: Optional regular expression flags that control the behavior of the regular expression. The following flags are supported:
    • i: case-insensitive: letters match both upper and lower case
    • m: multi-line mode: ^ and $ match begin/end of line
    • s: allow . to match \n
    • R: enables CRLF mode: when multi-line mode is enabled, \r\n is used
    • U: swap the meaning of x* and x*?
Example​
select regexp_match('Köln', '[a-zA-Z]ö[a-zA-Z]{2}');
+---------------------------------------------------------+
| regexp_match(Utf8("Köln"),Utf8("[a-zA-Z]ö[a-zA-Z]{2}")) |
+---------------------------------------------------------+
| [Köln]                                                  |
+---------------------------------------------------------+
SELECT regexp_match('aBc', '(b|d)', 'i');
+---------------------------------------------------+
| regexp_match(Utf8("aBc"),Utf8("(b|d)"),Utf8("i")) |
+---------------------------------------------------+
| [B]                                               |
+---------------------------------------------------+

Additional examples can be found here

regexp_replace​

Replaces substrings in a string that match a regular expression.

regexp_replace(str, regexp, replacement[, flags])
Arguments​
  • str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
  • regexp: Regular expression to match against. Can be a constant, column, or function.
  • replacement: Replacement string expression. Can be a constant, column, or function, and any combination of string operators.
  • flags: Optional regular expression flags that control the behavior of the regular expression. The following flags are supported:
    • g: (global) Search globally and don't return after the first match
    • i: case-insensitive: letters match both upper and lower case
    • m: multi-line mode: ^ and $ match begin/end of line
    • s: allow . to match \n
    • R: enables CRLF mode: when multi-line mode is enabled, \r\n is used
    • U: swap the meaning of x* and x*?
Example​
SELECT regexp_replace('foobarbaz', 'b(..)', 'X\\1Y', 'g');
+------------------------------------------------------------------------+
| regexp_replace(Utf8("foobarbaz"),Utf8("b(..)"),Utf8("X\1Y"),Utf8("g")) |
+------------------------------------------------------------------------+
| fooXarYXazY                                                            |
+------------------------------------------------------------------------+
SELECT regexp_replace('aBc', '(b|d)', 'Ab\\1a', 'i');
+-------------------------------------------------------------------+
| regexp_replace(Utf8("aBc"),Utf8("(b|d)"),Utf8("Ab\1a"),Utf8("i")) |
+-------------------------------------------------------------------+
| aAbBac                                                            |
+-------------------------------------------------------------------+

Additional examples can be found here

position​

Returns the position of substr in origstr (counting from 1). If substr does not appear in origstr, return 0.

position(substr in origstr)
Arguments​
  • substr: The pattern string.
  • origstr: The model string.
contains​

Return true if search_string is found within string.

contains(string, search_string)
Arguments​
  • string: The pattern string.
  • search_string: The model string.

Time and Date Functions​

now​

Returns the current UTC timestamp.

The now() return value is determined at query time and will return the same timestamp, no matter when in the query plan the function executes.

now()
current_date​

Returns the current UTC date.

The current_date() return value is determined at query time and will return the same date, no matter when in the query plan the function executes.

current_date()
Aliases​
  • today
today​

Alias of current_date.

current_time​

Returns the current UTC time.

The current_time() return value is determined at query time and will return the same time, no matter when in the query plan the function executes.

current_time()
date_bin​

Calculates time intervals and returns the start of the interval nearest to the specified timestamp. Use date_bin to downsample time series data by grouping rows into time-based "bins" or "windows" and applying an aggregate or selector function to each window.

For example, if you "bin" or "window" data into 15 minute intervals, an input timestamp of 2023-01-01T18:18:18Z will be updated to the start time of the 15 minute bin it is in: 2023-01-01T18:15:00Z.

date_bin(interval, expression, origin-timestamp)
Arguments​
  • interval: Bin interval.
  • expression: Time expression to operate on. Can be a constant, column, or function.
  • origin-timestamp: Optional. Starting point used to determine bin boundaries. If not specified defaults 1970-01-01T00:00:00Z (the UNIX epoch in UTC).

The following intervals are supported:

  • nanoseconds
  • microseconds
  • milliseconds
  • seconds
  • minutes
  • hours
  • days
  • weeks
  • months
  • years
  • century
date_trunc​

Truncates a timestamp value to a specified precision.

date_trunc(precision, expression)
Arguments​

  • precision: Time precision to truncate to. The following precisions are supported:

    • year / YEAR
    • quarter / QUARTER
    • month / MONTH
    • week / WEEK
    • day / DAY
    • hour / HOUR
    • minute / MINUTE
    • second / SECOND

  • expression: Time expression to operate on. Can be a constant, column, or function.

Aliases​
  • datetrunc
datetrunc​

Alias of date_trunc.

date_part​

Returns the specified part of the date as an integer.

date_part(part, expression)
Arguments​

  • part: Part of the date to return. The following date parts are supported:

    • year
    • quarter (emits value in inclusive range [1, 4] based on which quartile of the year the date is in)
    • month
    • week (week of the year)
    • day (day of the month)
    • hour
    • minute
    • second
    • millisecond
    • microsecond
    • nanosecond
    • dow (day of the week)
    • doy (day of the year)
    • epoch (seconds since Unix epoch)

  • expression: Time expression to operate on. Can be a constant, column, or function.

Aliases​
  • datepart
datepart​

Alias of date_part.

extract​

Returns a sub-field from a time value as an integer.

extract(field FROM source)

Equivalent to calling date_part('field', source). For example, these are equivalent:

extract(day FROM '2024-04-13'::date)
date_part('day', '2024-04-13'::date)

See date_part.

make_date​

Make a date from year/month/day component parts.

make_date(year, month, day)
Arguments​
  • year: Year to use when making the date. Can be a constant, column or function, and any combination of arithmetic operators.
  • month: Month to use when making the date. Can be a constant, column or function, and any combination of arithmetic operators.
  • day: Day to use when making the date. Can be a constant, column or function, and any combination of arithmetic operators.
Example​
> select make_date(2023, 1, 31);
+-------------------------------------------+
| make_date(Int64(2023),Int64(1),Int64(31)) |
+-------------------------------------------+
| 2023-01-31                                |
+-------------------------------------------+
> select make_date('2023', '01', '31');
+-----------------------------------------------+
| make_date(Utf8("2023"),Utf8("01"),Utf8("31")) |
+-----------------------------------------------+
| 2023-01-31                                    |
+-----------------------------------------------+

Additional examples can be found here

to_char​

Returns a string representation of a date, time, timestamp or duration based on a Chrono format. Unlike the PostgreSQL equivalent of this function numerical formatting is not supported.

to_char(expression, format)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function that results in a date, time, timestamp or duration.
  • format: A Chrono format string to use to convert the expression.
Example​
> > select to_char('2023-03-01'::date, '%d-%m-%Y');
+----------------------------------------------+
| to_char(Utf8("2023-03-01"),Utf8("%d-%m-%Y")) |
+----------------------------------------------+
| 01-03-2023                                   |
+----------------------------------------------+

Additional examples can be found here

Aliases​
  • date_format
to_date​

Converts a value to a date (YYYY-MM-DD). Supports strings, integer and double types as input. Strings are parsed as YYYY-MM-DD (e.g. '2023-07-20') if no Chrono formats are provided. Integers and doubles are interpreted as days since the unix epoch (1970-01-01T00:00:00Z). Returns the corresponding date.

Note: to_date returns Date32. The supported range for integer input is between -96465293 and 95026237. Supported range for string input is between 1677-09-21 and 2262-04-11 exclusive. To parse dates outside of that range use a Chrono format.

to_date(expression[, ..., format_n])
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • format_n: Optional Chrono format strings to use to parse the expression. Formats will be tried in the order they appear with the first successful one being returned. If none of the formats successfully parse the expression an error will be returned.
Example​
> select to_date('2023-01-31');
+-----------------------------+
| to_date(Utf8("2023-01-31")) |
+-----------------------------+
| 2023-01-31                  |
+-----------------------------+
> select to_date('2023/01/31', '%Y-%m-%d', '%Y/%m/%d');
+---------------------------------------------------------------+
| to_date(Utf8("2023/01/31"),Utf8("%Y-%m-%d"),Utf8("%Y/%m/%d")) |
+---------------------------------------------------------------+
| 2023-01-31                                                    |
+---------------------------------------------------------------+

Additional examples can be found here

to_timestamp​

Converts a value to a timestamp (YYYY-MM-DDT00:00:00Z). Supports strings, integer, unsigned integer, and double types as input. Strings are parsed as RFC3339 (e.g. '2023-07-20T05:44:00') if no [Chrono formats] are provided. Integers, unsigned integers, and doubles are interpreted as seconds since the unix epoch (1970-01-01T00:00:00Z). Returns the corresponding timestamp.

Note: to_timestamp returns Timestamp(Nanosecond). The supported range for integer input is between -9223372037 and 9223372036. Supported range for string input is between 1677-09-21T00:12:44.0 and 2262-04-11T23:47:16.0. Please use to_timestamp_seconds for the input outside of supported bounds.

to_timestamp(expression[, ..., format_n])
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • format_n: Optional Chrono format strings to use to parse the expression. Formats will be tried in the order they appear with the first successful one being returned. If none of the formats successfully parse the expression an error will be returned.
Example​
> select to_timestamp('2023-01-31T09:26:56.123456789-05:00');
+-----------------------------------------------------------+
| to_timestamp(Utf8("2023-01-31T09:26:56.123456789-05:00")) |
+-----------------------------------------------------------+
| 2023-01-31T14:26:56.123456789                             |
+-----------------------------------------------------------+
> select to_timestamp('03:59:00.123456789 05-17-2023', '%c', '%+', '%H:%M:%S%.f %m-%d-%Y');
+--------------------------------------------------------------------------------------------------------+
| to_timestamp(Utf8("03:59:00.123456789 05-17-2023"),Utf8("%c"),Utf8("%+"),Utf8("%H:%M:%S%.f %m-%d-%Y")) |
+--------------------------------------------------------------------------------------------------------+
| 2023-05-17T03:59:00.123456789                                                                          |
+--------------------------------------------------------------------------------------------------------+

Additional examples can be found here

to_timestamp_millis​

Converts a value to a timestamp (YYYY-MM-DDT00:00:00.000Z). Supports strings, integer, and unsigned integer types as input. Strings are parsed as RFC3339 (e.g. '2023-07-20T05:44:00') if no Chrono formats are provided. Integers and unsigned integers are interpreted as milliseconds since the unix epoch (1970-01-01T00:00:00Z). Returns the corresponding timestamp.

to_timestamp_millis(expression[, ..., format_n])
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • format_n: Optional Chrono format strings to use to parse the expression. Formats will be tried in the order they appear with the first successful one being returned. If none of the formats successfully parse the expression an error will be returned.
Example​
> select to_timestamp_millis('2023-01-31T09:26:56.123456789-05:00');
+------------------------------------------------------------------+
| to_timestamp_millis(Utf8("2023-01-31T09:26:56.123456789-05:00")) |
+------------------------------------------------------------------+
| 2023-01-31T14:26:56.123                                          |
+------------------------------------------------------------------+
> select to_timestamp_millis('03:59:00.123456789 05-17-2023', '%c', '%+', '%H:%M:%S%.f %m-%d-%Y');
+---------------------------------------------------------------------------------------------------------------+
| to_timestamp_millis(Utf8("03:59:00.123456789 05-17-2023"),Utf8("%c"),Utf8("%+"),Utf8("%H:%M:%S%.f %m-%d-%Y")) |
+---------------------------------------------------------------------------------------------------------------+
| 2023-05-17T03:59:00.123                                                                                       |
+---------------------------------------------------------------------------------------------------------------+

Additional examples can be found here

to_timestamp_micros​

Converts a value to a timestamp (YYYY-MM-DDT00:00:00.000000Z). Supports strings, integer, and unsigned integer types as input. Strings are parsed as RFC3339 (e.g. '2023-07-20T05:44:00') if no Chrono formats are provided. Integers and unsigned integers are interpreted as microseconds since the unix epoch (1970-01-01T00:00:00Z) Returns the corresponding timestamp.

to_timestamp_micros(expression[, ..., format_n])
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • format_n: Optional Chrono format strings to use to parse the expression. Formats will be tried in the order they appear with the first successful one being returned. If none of the formats successfully parse the expression an error will be returned.
Example​
> select to_timestamp_micros('2023-01-31T09:26:56.123456789-05:00');
+------------------------------------------------------------------+
| to_timestamp_micros(Utf8("2023-01-31T09:26:56.123456789-05:00")) |
+------------------------------------------------------------------+
| 2023-01-31T14:26:56.123456                                       |
+------------------------------------------------------------------+
> select to_timestamp_micros('03:59:00.123456789 05-17-2023', '%c', '%+', '%H:%M:%S%.f %m-%d-%Y');
+---------------------------------------------------------------------------------------------------------------+
| to_timestamp_micros(Utf8("03:59:00.123456789 05-17-2023"),Utf8("%c"),Utf8("%+"),Utf8("%H:%M:%S%.f %m-%d-%Y")) |
+---------------------------------------------------------------------------------------------------------------+
| 2023-05-17T03:59:00.123456                                                                                    |
+---------------------------------------------------------------------------------------------------------------+

Additional examples can be found here

to_timestamp_nanos​

Converts a value to a timestamp (YYYY-MM-DDT00:00:00.000000000Z). Supports strings, integer, and unsigned integer types as input. Strings are parsed as RFC3339 (e.g. '2023-07-20T05:44:00') if no Chrono formats are provided. Integers and unsigned integers are interpreted as nanoseconds since the unix epoch (1970-01-01T00:00:00Z). Returns the corresponding timestamp.

to_timestamp_nanos(expression[, ..., format_n])
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • format_n: Optional Chrono format strings to use to parse the expression. Formats will be tried in the order they appear with the first successful one being returned. If none of the formats successfully parse the expression an error will be returned.
Example​
> select to_timestamp_nanos('2023-01-31T09:26:56.123456789-05:00');
+-----------------------------------------------------------------+
| to_timestamp_nanos(Utf8("2023-01-31T09:26:56.123456789-05:00")) |
+-----------------------------------------------------------------+
| 2023-01-31T14:26:56.123456789                                   |
+-----------------------------------------------------------------+
> select to_timestamp_nanos('03:59:00.123456789 05-17-2023', '%c', '%+', '%H:%M:%S%.f %m-%d-%Y');
+--------------------------------------------------------------------------------------------------------------+
| to_timestamp_nanos(Utf8("03:59:00.123456789 05-17-2023"),Utf8("%c"),Utf8("%+"),Utf8("%H:%M:%S%.f %m-%d-%Y")) |
+--------------------------------------------------------------------------------------------------------------+
| 2023-05-17T03:59:00.123456789                                                                                |
+---------------------------------------------------------------------------------------------------------------+

Additional examples can be found here

to_timestamp_seconds​

Converts a value to a timestamp (YYYY-MM-DDT00:00:00.000Z). Supports strings, integer, and unsigned integer types as input. Strings are parsed as RFC3339 (e.g. '2023-07-20T05:44:00') if no Chrono formats are provided. Integers and unsigned integers are interpreted as seconds since the unix epoch (1970-01-01T00:00:00Z). Returns the corresponding timestamp.

to_timestamp_seconds(expression[, ..., format_n])
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • format_n: Optional Chrono format strings to use to parse the expression. Formats will be tried in the order they appear with the first successful one being returned. If none of the formats successfully parse the expression an error will be returned.
Example​
> select to_timestamp_seconds('2023-01-31T09:26:56.123456789-05:00');
+-------------------------------------------------------------------+
| to_timestamp_seconds(Utf8("2023-01-31T09:26:56.123456789-05:00")) |
+-------------------------------------------------------------------+
| 2023-01-31T14:26:56                                               |
+-------------------------------------------------------------------+
> select to_timestamp_seconds('03:59:00.123456789 05-17-2023', '%c', '%+', '%H:%M:%S%.f %m-%d-%Y');
+----------------------------------------------------------------------------------------------------------------+
| to_timestamp_seconds(Utf8("03:59:00.123456789 05-17-2023"),Utf8("%c"),Utf8("%+"),Utf8("%H:%M:%S%.f %m-%d-%Y")) |
+----------------------------------------------------------------------------------------------------------------+
| 2023-05-17T03:59:00                                                                                            |
+----------------------------------------------------------------------------------------------------------------+

Additional examples can be found here

from_unixtime​

Converts an integer to RFC3339 timestamp format (YYYY-MM-DDT00:00:00.000000000Z). Integers and unsigned integers are interpreted as nanoseconds since the unix epoch (1970-01-01T00:00:00Z) return the corresponding timestamp.

from_unixtime(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
to_unixtime​

Converts a value to seconds since the unix epoch (1970-01-01T00:00:00Z). Supports strings, dates, timestamps and double types as input. Strings are parsed as RFC3339 (e.g. '2023-07-20T05:44:00') if no [Chrono formats] are provided.

to_unixtime(expression[, ..., format_n])
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • format_n: Optional Chrono format strings to use to parse the expression. Formats will be tried in the order they appear with the first successful one being returned. If none of the formats successfully parse the expression an error will be returned.
Example​
> select to_unixtime('2020-09-08T12:00:00+00:00');
+------------------------------------------------+
| to_unixtime(Utf8("2020-09-08T12:00:00+00:00")) |
+------------------------------------------------+
| 1599566400                                     |
+------------------------------------------------+
> select to_unixtime('01-14-2023 01:01:30+05:30', '%q', '%d-%m-%Y %H/%M/%S', '%+', '%m-%d-%Y %H:%M:%S%#z');
+-----------------------------------------------------------------------------------------------------------------------------+
| to_unixtime(Utf8("01-14-2023 01:01:30+05:30"),Utf8("%q"),Utf8("%d-%m-%Y %H/%M/%S"),Utf8("%+"),Utf8("%m-%d-%Y %H:%M:%S%#z")) |
+-----------------------------------------------------------------------------------------------------------------------------+
| 1673638290                                                                                                                  |
+-----------------------------------------------------------------------------------------------------------------------------+

Array Functions​

array_append​

Appends an element to the end of an array.

array_append(array, element)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • element: Element to append to the array.
Example​
> select array_append([1, 2, 3], 4);
+--------------------------------------+
| array_append(List([1,2,3]),Int64(4)) |
+--------------------------------------+
| [1, 2, 3, 4]                         |
+--------------------------------------+
Aliases​
  • array_push_back
  • list_append
  • list_push_back
array_sort​

Sort array.

array_sort(array, desc, nulls_first)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • desc: Whether to sort in descending order(ASC or DESC).
  • nulls_first: Whether to sort nulls first(NULLS FIRST or NULLS LAST).
Example​
> select array_sort([3, 1, 2]);
+-----------------------------+
| array_sort(List([3,1,2]))   |
+-----------------------------+
| [1, 2, 3]                   |
+-----------------------------+
Aliases​
  • list_sort
array_resize​

Resizes the list to contain size elements. Initializes new elements with value or empty if value is not set.

array_resize(array, size, value)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • size: New size of given array.
  • value: Defines new elements' value or empty if value is not set.
Example​
> select array_resize([1, 2, 3], 5, 0);
+-------------------------------------+
| array_resize(List([1,2,3],5,0))     |
+-------------------------------------+
| [1, 2, 3, 0, 0]                     |
+-------------------------------------+
Aliases​
  • list_resize
array_cat​

Alias of array_concat.

array_concat​

Concatenates arrays.

array_concat(array[, ..., array_n])
Arguments​
  • array: Array expression to concatenate. Can be a constant, column, or function, and any combination of array operators.
  • array_n: Subsequent array column or literal array to concatenate.
Example​
> select array_concat([1, 2], [3, 4], [5, 6]);
+---------------------------------------------------+
| array_concat(List([1,2]),List([3,4]),List([5,6])) |
+---------------------------------------------------+
| [1, 2, 3, 4, 5, 6]                                |
+---------------------------------------------------+
Aliases​
  • array_cat
  • list_cat
  • list_concat
array_contains​

Alias of array_has.

array_has​

Returns true if the array contains the element

array_has(array, element)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • element: Scalar or Array expression. Can be a constant, column, or function, and any combination of array operators.
Aliases​
  • list_has
array_has_all​

Returns true if all elements of sub-array exist in array

array_has_all(array, sub-array)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • sub-array: Array expression. Can be a constant, column, or function, and any combination of array operators.
Aliases​
  • list_has_all
array_has_any​

Returns true if any elements exist in both arrays

array_has_any(array, sub-array)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • sub-array: Array expression. Can be a constant, column, or function, and any combination of array operators.
Aliases​
  • list_has_any
array_dims​

Returns an array of the array's dimensions.

array_dims(array)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
Example​
> select array_dims([[1, 2, 3], [4, 5, 6]]);
+---------------------------------+
| array_dims(List([1,2,3,4,5,6])) |
+---------------------------------+
| [2, 3]                          |
+---------------------------------+
Aliases​
  • list_dims
array_distinct​

Returns distinct values from the array after removing duplicates.

array_distinct(array)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
Example​
> select array_distinct([1, 3, 2, 3, 1, 2, 4]);
+---------------------------------+
| array_distinct(List([1,2,3,4])) |
+---------------------------------+
| [1, 2, 3, 4]                    |
+---------------------------------+
Aliases​
  • list_distinct
array_element​

Extracts the element with the index n from the array.

array_element(array, index)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • index: Index to extract the element from the array.
Example​
> select array_element([1, 2, 3, 4], 3);
+-----------------------------------------+
| array_element(List([1,2,3,4]),Int64(3)) |
+-----------------------------------------+
| 3                                       |
+-----------------------------------------+
Aliases​
  • array_extract
  • list_element
  • list_extract
array_extract​

Alias of array_element.

array_fill​

Returns an array filled with copies of the given value.

DEPRECATED: use array_repeat instead!

array_fill(element, array)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • element: Element to copy to the array.
flatten​

Converts an array of arrays to a flat array

  • Applies to any depth of nested arrays
  • Does not change arrays that are already flat

The flattened array contains all the elements from all source arrays.

Arguments​
  • array: Array expression Can be a constant, column, or function, and any combination of array operators.
flatten(array)
array_indexof​

Alias of array_position.

array_intersect​

Returns an array of elements in the intersection of array1 and array2.

array_intersect(array1, array2)
Arguments​
  • array1: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • array2: Array expression. Can be a constant, column, or function, and any combination of array operators.
Example​
> select array_intersect([1, 2, 3, 4], [5, 6, 3, 4]);
+----------------------------------------------------+
| array_intersect([1, 2, 3, 4], [5, 6, 3, 4]);       |
+----------------------------------------------------+
| [3, 4]                                             |
+----------------------------------------------------+
> select array_intersect([1, 2, 3, 4], [5, 6, 7, 8]);
+----------------------------------------------------+
| array_intersect([1, 2, 3, 4], [5, 6, 7, 8]);       |
+----------------------------------------------------+
| []                                                 |
+----------------------------------------------------+
Aliases​
  • list_intersect
array_join​

Alias of array_to_string.

array_length​

Returns the length of the array dimension.

array_length(array, dimension)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • dimension: Array dimension.
Example​
> select array_length([1, 2, 3, 4, 5]);
+---------------------------------+
| array_length(List([1,2,3,4,5])) |
+---------------------------------+
| 5                               |
+---------------------------------+
Aliases​
  • list_length
array_ndims​

Returns the number of dimensions of the array.

array_ndims(array, element)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
Example​
> select array_ndims([[1, 2, 3], [4, 5, 6]]);
+----------------------------------+
| array_ndims(List([1,2,3,4,5,6])) |
+----------------------------------+
| 2                                |
+----------------------------------+
Aliases​
  • list_ndims
array_prepend​

Prepends an element to the beginning of an array.

array_prepend(element, array)
Arguments​
  • element: Element to prepend to the array.
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
Example​
> select array_prepend(1, [2, 3, 4]);
+---------------------------------------+
| array_prepend(Int64(1),List([2,3,4])) |
+---------------------------------------+
| [1, 2, 3, 4]                          |
+---------------------------------------+
Aliases​
  • array_push_front
  • list_prepend
  • list_push_front
array_pop_front​

Returns the array without the first element.

array_pop_front(array)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
Example​
> select array_pop_front([1, 2, 3]);
+-------------------------------+
| array_pop_front(List([1,2,3])) |
+-------------------------------+
| [2, 3]                        |
+-------------------------------+
Aliases​
  • list_pop_front
array_pop_back​

Returns the array without the last element.

array_pop_back(array)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
Example​
> select array_pop_back([1, 2, 3]);
+-------------------------------+
| array_pop_back(List([1,2,3])) |
+-------------------------------+
| [1, 2]                        |
+-------------------------------+
Aliases​
  • list_pop_back
array_position​

Returns the position of the first occurrence of the specified element in the array.

array_position(array, element)
array_position(array, element, index)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • element: Element to search for position in the array.
  • index: Index at which to start searching.
Example​
> select array_position([1, 2, 2, 3, 1, 4], 2);
+----------------------------------------------+
| array_position(List([1,2,2,3,1,4]),Int64(2)) |
+----------------------------------------------+
| 2                                            |
+----------------------------------------------+
Aliases​
  • array_indexof
  • list_indexof
  • list_position
array_positions​

Searches for an element in the array, returns all occurrences.

array_positions(array, element)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • element: Element to search for positions in the array.
Example​
> select array_positions([1, 2, 2, 3, 1, 4], 2);
+-----------------------------------------------+
| array_positions(List([1,2,2,3,1,4]),Int64(2)) |
+-----------------------------------------------+
| [2, 3]                                        |
+-----------------------------------------------+
Aliases​
  • list_positions
array_push_back​

Alias of array_append.

array_push_front​

Alias of array_prepend.

array_repeat​

Returns an array containing element count times.

array_repeat(element, count)
Arguments​
  • element: Element expression. Can be a constant, column, or function, and any combination of array operators.
  • count: Value of how many times to repeat the element.
Example​
> select array_repeat(1, 3);
+---------------------------------+
| array_repeat(Int64(1),Int64(3)) |
+---------------------------------+
| [1, 1, 1]                       |
+---------------------------------+
> select array_repeat([1, 2], 2);
+------------------------------------+
| array_repeat(List([1,2]),Int64(2)) |
+------------------------------------+
| [[1, 2], [1, 2]]                   |
+------------------------------------+
Aliases​
  • list_repeat
array_remove​

Removes the first element from the array equal to the given value.

array_remove(array, element)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • element: Element to be removed from the array.
Example​
> select array_remove([1, 2, 2, 3, 2, 1, 4], 2);
+----------------------------------------------+
| array_remove(List([1,2,2,3,2,1,4]),Int64(2)) |
+----------------------------------------------+
| [1, 2, 3, 2, 1, 4]                           |
+----------------------------------------------+
Aliases​
  • list_remove
array_remove_n​

Removes the first max elements from the array equal to the given value.

array_remove_n(array, element, max)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • element: Element to be removed from the array.
  • max: Number of first occurrences to remove.
Example​
> select array_remove_n([1, 2, 2, 3, 2, 1, 4], 2, 2);
+---------------------------------------------------------+
| array_remove_n(List([1,2,2,3,2,1,4]),Int64(2),Int64(2)) |
+---------------------------------------------------------+
| [1, 3, 2, 1, 4]                                         |
+---------------------------------------------------------+
Aliases​
  • list_remove_n
array_remove_all​

Removes all elements from the array equal to the given value.

array_remove_all(array, element)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • element: Element to be removed from the array.
Example​
> select array_remove_all([1, 2, 2, 3, 2, 1, 4], 2);
+--------------------------------------------------+
| array_remove_all(List([1,2,2,3,2,1,4]),Int64(2)) |
+--------------------------------------------------+
| [1, 3, 1, 4]                                     |
+--------------------------------------------------+
Aliases​
  • list_remove_all
array_replace​

Replaces the first occurrence of the specified element with another specified element.

array_replace(array, from, to)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • from: Initial element.
  • to: Final element.
Example​
> select array_replace([1, 2, 2, 3, 2, 1, 4], 2, 5);
+--------------------------------------------------------+
| array_replace(List([1,2,2,3,2,1,4]),Int64(2),Int64(5)) |
+--------------------------------------------------------+
| [1, 5, 2, 3, 2, 1, 4]                                  |
+--------------------------------------------------------+
Aliases​
  • list_replace
array_replace_n​

Replaces the first max occurrences of the specified element with another specified element.

array_replace_n(array, from, to, max)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • from: Initial element.
  • to: Final element.
  • max: Number of first occurrences to replace.
Example​
> select array_replace_n([1, 2, 2, 3, 2, 1, 4], 2, 5, 2);
+-------------------------------------------------------------------+
| array_replace_n(List([1,2,2,3,2,1,4]),Int64(2),Int64(5),Int64(2)) |
+-------------------------------------------------------------------+
| [1, 5, 5, 3, 2, 1, 4]                                             |
+-------------------------------------------------------------------+
Aliases​
  • list_replace_n
array_replace_all​

Replaces all occurrences of the specified element with another specified element.

array_replace_all(array, from, to)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • from: Initial element.
  • to: Final element.
Example​
> select array_replace_all([1, 2, 2, 3, 2, 1, 4], 2, 5);
+------------------------------------------------------------+
| array_replace_all(List([1,2,2,3,2,1,4]),Int64(2),Int64(5)) |
+------------------------------------------------------------+
| [1, 5, 5, 3, 5, 1, 4]                                      |
+------------------------------------------------------------+
Aliases​
  • list_replace_all
array_reverse​

Returns the array with the order of the elements reversed.

array_reverse(array)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
Example​
> select array_reverse([1, 2, 3, 4]);
+------------------------------------------------------------+
| array_reverse(List([1, 2, 3, 4]))                          |
+------------------------------------------------------------+
| [4, 3, 2, 1]                                               |
+------------------------------------------------------------+
Aliases​
  • list_reverse
array_slice​

Returns a slice of the array based on 1-indexed start and end positions.

array_slice(array, begin, end)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • begin: Index of the first element. If negative, it counts backward from the end of the array.
  • end: Index of the last element. If negative, it counts backward from the end of the array.
  • stride: Stride of the array slice. The default is 1.
Example​
> select array_slice([1, 2, 3, 4, 5, 6, 7, 8], 3, 6);
+--------------------------------------------------------+
| array_slice(List([1,2,3,4,5,6,7,8]),Int64(3),Int64(6)) |
+--------------------------------------------------------+
| [3, 4, 5, 6]                                           |
+--------------------------------------------------------+
Aliases​
  • list_slice
array_to_string​

Converts each element to its text representation.

array_to_string(array, delimiter)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • delimiter: Array element separator.
Example​
> select array_to_string([[1, 2, 3, 4], [5, 6, 7, 8]], ',');
+----------------------------------------------------+
| array_to_string(List([1,2,3,4,5,6,7,8]),Utf8(",")) |
+----------------------------------------------------+
| 1,2,3,4,5,6,7,8                                    |
+----------------------------------------------------+
Aliases​
  • array_join
  • list_join
  • list_to_string
array_union​

Returns an array of elements that are present in both arrays (all elements from both arrays) with out duplicates.

array_union(array1, array2)
Arguments​
  • array1: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • array2: Array expression. Can be a constant, column, or function, and any combination of array operators.
Example​
> select array_union([1, 2, 3, 4], [5, 6, 3, 4]);
+----------------------------------------------------+
| array_union([1, 2, 3, 4], [5, 6, 3, 4]);           |
+----------------------------------------------------+
| [1, 2, 3, 4, 5, 6]                                 |
+----------------------------------------------------+
> select array_union([1, 2, 3, 4], [5, 6, 7, 8]);
+----------------------------------------------------+
| array_union([1, 2, 3, 4], [5, 6, 7, 8]);           |
+----------------------------------------------------+
| [1, 2, 3, 4, 5, 6, 7, 8]                           |
+----------------------------------------------------+
Aliases​
  • list_union
array_except​

Returns an array of the elements that appear in the first array but not in the second.

array_except(array1, array2)
Arguments​
  • array1: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • array2: Array expression. Can be a constant, column, or function, and any combination of array operators.
Example​
> select array_except([1, 2, 3, 4], [5, 6, 3, 4]);
+----------------------------------------------------+
| array_except([1, 2, 3, 4], [5, 6, 3, 4]);           |
+----------------------------------------------------+
| [1, 2]                                 |
+----------------------------------------------------+
> select array_except([1, 2, 3, 4], [3, 4, 5, 6]);
+----------------------------------------------------+
| array_except([1, 2, 3, 4], [3, 4, 5, 6]);           |
+----------------------------------------------------+
| [1, 2]                                 |
+----------------------------------------------------+
Aliases​
  • list_except
cardinality​

Returns the total number of elements in the array.

cardinality(array)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
Example​
> select cardinality([[1, 2, 3, 4], [5, 6, 7, 8]]);
+--------------------------------------+
| cardinality(List([1,2,3,4,5,6,7,8])) |
+--------------------------------------+
| 8                                    |
+--------------------------------------+
empty​

Returns 1 for an empty array or 0 for a non-empty array.

empty(array)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
Example​
> select empty([1]);
+------------------+
| empty(List([1])) |
+------------------+
| 0                |
+------------------+
Aliases​
  • array_empty,
  • list_empty
generate_series​

Similar to the range function, but it includes the upper bound.

generate_series(start, stop, step)
Arguments​
  • start: start of the range
  • end: end of the range (included)
  • step: increase by step (can not be 0)
Example​
> select generate_series(1,3);
+------------------------------------+
| generate_series(Int64(1),Int64(3)) |
+------------------------------------+
| [1, 2, 3]                          |
+------------------------------------+
list_append​

Alias of array_append.

list_cat​

Alias of array_concat.

list_concat​

Alias of array_concat.

list_dims​

Alias of array_dims.

list_distinct​

Alias of array_dims.

list_element​

Alias of array_element.

list_empty​

Alias of empty.

list_except​

Alias of array_element.

list_extract​

Alias of array_element.

list_has​

Alias of array_has.

list_has_all​

Alias of array_has_all.

list_has_any​

Alias of array_has_any.

list_indexof​

Alias of array_position.

list_intersect​

Alias of array_position.

list_join​

Alias of array_to_string.

list_length​

Alias of array_length.

list_ndims​

Alias of array_ndims.

list_prepend​

Alias of array_prepend.

list_pop_back​

Alias of array_pop_back.

list_pop_front​

Alias of array_pop_front.

list_position​

Alias of array_position.

list_positions​

Alias of array_positions.

list_push_back​

Alias of array_append.

list_push_front​

Alias of array_prepend.

list_repeat​

Alias of array_repeat.

list_resize​

Alias of array_resize.

list_remove​

Alias of array_remove.

list_remove_n​

Alias of array_remove_n.

list_remove_all​

Alias of array_remove_all.

list_replace​

Alias of array_replace.

list_replace_n​

Alias of array_replace_n.

list_replace_all​

Alias of array_replace_all.

list_reverse​

Alias of array_reverse.

list_slice​

Alias of array_slice.

list_sort​

Alias of array_sort.

list_to_string​

Alias of array_to_string.

list_union​

Alias of array_union.

make_array​

Returns an Arrow array using the specified input expressions.

make_array(expression1[, ..., expression_n])
array_empty​

Alias of empty.

Arguments​
  • expression_n: Expression to include in the output array. Can be a constant, column, or function, and any combination of arithmetic or string operators.
Example​
> select make_array(1, 2, 3, 4, 5);
+----------------------------------------------------------+
| make_array(Int64(1),Int64(2),Int64(3),Int64(4),Int64(5)) |
+----------------------------------------------------------+
| [1, 2, 3, 4, 5]                                          |
+----------------------------------------------------------+
Aliases​
  • make_list
make_list​

Alias of make_array.

string_to_array​

Splits a string in to an array of substrings based on a delimiter. Any substrings matching the optional null_str argument are replaced with NULL. SELECT string_to_array('abc##def', '##') or SELECT string_to_array('abc def', ' ', 'def')

starts_with(str, delimiter[, null_str])
Arguments​
  • str: String expression to split.
  • delimiter: Delimiter string to split on.
  • null_str: Substring values to be replaced with NULL
Aliases​
  • string_to_list
string_to_list​

Alias of string_to_array.

trim_array​

Removes the last n elements from the array.

DEPRECATED: use array_slice instead!

trim_array(array, n)
Arguments​
  • array: Array expression. Can be a constant, column, or function, and any combination of array operators.
  • n: Element to trim the array.
unnest​

Transforms an array into rows.

Arguments​
  • array: Array expression to unnest. Can be a constant, column, or function, and any combination of array operators.
Examples​
> select unnest(make_array(1, 2, 3, 4, 5));
+------------------------------------------------------------------+
| unnest(make_array(Int64(1),Int64(2),Int64(3),Int64(4),Int64(5))) |
+------------------------------------------------------------------+
| 1                                                                |
| 2                                                                |
| 3                                                                |
| 4                                                                |
| 5                                                                |
+------------------------------------------------------------------+
> select unnest(range(0, 10));
+-----------------------------------+
| unnest(range(Int64(0),Int64(10))) |
+-----------------------------------+
| 0                                 |
| 1                                 |
| 2                                 |
| 3                                 |
| 4                                 |
| 5                                 |
| 6                                 |
| 7                                 |
| 8                                 |
| 9                                 |
+-----------------------------------+
range​

Returns an Arrow array between start and stop with step. SELECT range(2, 10, 3) -> [2, 5, 8] or SELECT range(DATE '1992-09-01', DATE '1993-03-01', INTERVAL '1' MONTH);

The range start..end contains all values with start <= x < end. It is empty if start >= end.

Step can not be 0 (then the range will be nonsense.).

Note that when the required range is a number, it accepts (stop), (start, stop), and (start, stop, step) as parameters, but when the required range is a date, it must be 3 non-NULL parameters. For example,

SELECT range(3);
SELECT range(1,5);
SELECT range(1,5,1);

are allowed in number ranges

but in date ranges, only

SELECT range(DATE '1992-09-01', DATE '1993-03-01', INTERVAL '1' MONTH);

is allowed, and

SELECT range(DATE '1992-09-01', DATE '1993-03-01', NULL);
SELECT range(NULL, DATE '1993-03-01', INTERVAL '1' MONTH);
SELECT range(DATE '1992-09-01', NULL, INTERVAL '1' MONTH);

are not allowed

Arguments​
  • start: start of the range
  • end: end of the range (not included)
  • step: increase by step (can not be 0)
Aliases​
  • generate_series

Struct Functions​

struct​

Returns an Arrow struct using the specified input expressions optionally named. Fields in the returned struct use the optional name or the cN naming convention. For example: c0, c1, c2, etc.

struct(expression1[, ..., expression_n])

For example, this query converts two columns a and b to a single column with a struct type of fields field_a and c1:

select * from t;
+---+---+
| a | b |
+---+---+
| 1 | 2 |
| 3 | 4 |
+---+---+

-- use default names `c0`, `c1`
> select struct(a, b) from t;
+-----------------+
| struct(t.a,t.b) |
+-----------------+
| {c0: 1, c1: 2}  |
| {c0: 3, c1: 4}  |
+-----------------+

-- name the first field `field_a`
select struct(a as field_a, b) from t;
+--------------------------------------------------+
| named_struct(Utf8("field_a"),t.a,Utf8("c1"),t.b) |
+--------------------------------------------------+
| {field_a: 1, c1: 2}                              |
| {field_a: 3, c1: 4}                              |
+--------------------------------------------------+
Arguments​
  • expression_n: Expression to include in the output struct. Can be a constant, column, or function, any combination of arithmetic or string operators, or a named expression of previous listed .
named_struct​

Returns an Arrow struct using the specified name and input expressions pairs.

named_struct(expression1_name, expression1_input[, ..., expression_n_name, expression_n_input])

For example, this query converts two columns a and b to a single column with a struct type of fields field_a and field_b:

select * from t;
+---+---+
| a | b |
+---+---+
| 1 | 2 |
| 3 | 4 |
+---+---+

select named_struct('field_a', a, 'field_b', b) from t;
+-------------------------------------------------------+
| named_struct(Utf8("field_a"),t.a,Utf8("field_b"),t.b) |
+-------------------------------------------------------+
| {field_a: 1, field_b: 2}                              |
| {field_a: 3, field_b: 4}                              |
+-------------------------------------------------------+
Arguments​
  • expression_n_name: Name of the column field. Must be a constant string.
  • expression_n_input: Expression to include in the output struct. Can be a constant, column, or function, and any combination of arithmetic or string operators.
unnest (struct)​

Unwraps struct fields into columns.

Arguments​
  • struct: Object expression to unnest. Can be a constant, column, or function, and any combination of object operators.
Examples​
> select * from foo;
+---------------------+
| column1             |
+---------------------+
| {a: 5, b: a string} |
+---------------------+

> select unnest(column1) from foo;
+-----------------------+-----------------------+
| unnest(foo.column1).a | unnest(foo.column1).b |
+-----------------------+-----------------------+
| 5                     | a string              |
+-----------------------+-----------------------+

Hashing Functions​

digest​

Computes the binary hash of an expression using the specified algorithm.

digest(expression, algorithm)
Arguments​

  • expression: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.

  • algorithm: String expression specifying algorithm to use. Must be one of:

    • md5
    • sha224
    • sha256
    • sha384
    • sha512
    • blake2s
    • blake2b
    • blake3
md5​

Computes an MD5 128-bit checksum for a string expression.

md5(expression)
Arguments​
  • expression: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
sha224​

Computes the SHA-224 hash of a binary string.

sha224(expression)
Arguments​
  • expression: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
sha256​

Computes the SHA-256 hash of a binary string.

sha256(expression)
Arguments​
  • expression: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
sha384​

Computes the SHA-384 hash of a binary string.

sha384(expression)
Arguments​
  • expression: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
sha512​

Computes the SHA-512 hash of a binary string.

sha512(expression)
Arguments​
  • expression: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.

Other Functions​

arrow_cast​

Casts a value to a specific Arrow data type:

arrow_cast(expression, datatype)
Arguments​
  • expression: Expression to cast. Can be a constant, column, or function, and any combination of arithmetic or string operators.
  • datatype: Arrow data type name to cast to, as a string. The format is the same as that returned by [arrow_typeof]
Example​
> select arrow_cast(-5, 'Int8') as a,
  arrow_cast('foo', 'Dictionary(Int32, Utf8)') as b,
  arrow_cast('bar', 'LargeUtf8') as c,
  arrow_cast('2023-01-02T12:53:02', 'Timestamp(Microsecond, Some("+08:00"))') as d
  ;
+----+-----+-----+---------------------------+
| a  | b   | c   | d                         |
+----+-----+-----+---------------------------+
| -5 | foo | bar | 2023-01-02T12:53:02+08:00 |
+----+-----+-----+---------------------------+
1 row in set. Query took 0.001 seconds.
arrow_typeof​

Returns the name of the underlying Arrow data type of the expression:

arrow_typeof(expression)
Arguments​
  • expression: Expression to evaluate. Can be a constant, column, or function, and any combination of arithmetic or string operators.
Example​
> select arrow_typeof('foo'), arrow_typeof(1);
+---------------------------+------------------------+
| arrow_typeof(Utf8("foo")) | arrow_typeof(Int64(1)) |
+---------------------------+------------------------+
| Utf8                      | Int64                  |
+---------------------------+------------------------+
1 row in set. Query took 0.001 seconds.

Aggregate Functions​

Aggregate functions operate on a set of values to compute a single result.

General​

avg​

Returns the average of numeric values in the specified column.

avg(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
Aliases​
  • mean
bit_and​

Computes the bitwise AND of all non-null input values.

bit_and(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
bit_or​

Computes the bitwise OR of all non-null input values.

bit_or(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
bit_xor​

Computes the bitwise exclusive OR of all non-null input values.

bit_xor(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
bool_and​

Returns true if all non-null input values are true, otherwise false.

bool_and(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
bool_or​

Returns true if any non-null input value is true, otherwise false.

bool_or(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
count​

Returns the number of non-null values in the specified column.

To include null values in the total count, use count(*).

count(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
max​

Returns the maximum value in the specified column.

max(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
mean​

Alias of avg.

median​

Returns the median value in the specified column.

median(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
min​

Returns the minimum value in the specified column.

min(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
sum​

Returns the sum of all values in the specified column.

sum(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
array_agg​

Returns an array created from the expression elements. If ordering requirement is given, elements are inserted in the order of required ordering.

array_agg(expression [ORDER BY expression])
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
first_value​

Returns the first element in an aggregation group according to the requested ordering. If no ordering is given, returns an arbitrary element from the group.

first_value(expression [ORDER BY expression])
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
last_value​

Returns the last element in an aggregation group according to the requested ordering. If no ordering is given, returns an arbitrary element from the group.

last_value(expression [ORDER BY expression])
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.

Statistical​

corr​

Returns the coefficient of correlation between two numeric values.

corr(expression1, expression2)
Arguments​
  • expression1: First expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression2: Second expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
covar​

Returns the covariance of a set of number pairs.

covar(expression1, expression2)
Arguments​
  • expression1: First expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression2: Second expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
covar_pop​

Returns the population covariance of a set of number pairs.

covar_pop(expression1, expression2)
Arguments​
  • expression1: First expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression2: Second expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
covar_samp​

Returns the sample covariance of a set of number pairs.

covar_samp(expression1, expression2)
Arguments​
  • expression1: First expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression2: Second expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
stddev​

Returns the standard deviation of a set of numbers.

stddev(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
stddev_pop​

Returns the population standard deviation of a set of numbers.

stddev_pop(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
stddev_samp​

Returns the sample standard deviation of a set of numbers.

stddev_samp(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
var​

Returns the statistical variance of a set of numbers.

var(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
var_pop​

Returns the statistical population variance of a set of numbers.

var_pop(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
var_samp​

Returns the statistical sample variance of a set of numbers.

var_samp(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_slope​

Returns the slope of the linear regression line for non-null pairs in aggregate columns. Given input column Y and X: regr_slope(Y, X) returns the slope (k in Y = k*X + b) using minimal RSS fitting.

regr_slope(expression1, expression2)
Arguments​
  • expression_y: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression_x: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_avgx​

Computes the average of the independent variable (input) expression_x for the non-null paired data points.

regr_avgx(expression_y, expression_x)
Arguments​
  • expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_avgy​

Computes the average of the dependent variable (output) expression_y for the non-null paired data points.

regr_avgy(expression_y, expression_x)
Arguments​
  • expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_count​

Counts the number of non-null paired data points.

regr_count(expression_y, expression_x)
Arguments​
  • expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_intercept​

Computes the y-intercept of the linear regression line. For the equation (y = kx + b), this function returns b.

regr_intercept(expression_y, expression_x)
Arguments​
  • expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_r2​

Computes the square of the correlation coefficient between the independent and dependent variables.

regr_r2(expression_y, expression_x)
Arguments​
  • expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_sxx​

Computes the sum of squares of the independent variable.

regr_sxx(expression_y, expression_x)
Arguments​
  • expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_syy​

Computes the sum of squares of the dependent variable.

regr_syy(expression_y, expression_x)
Arguments​
  • expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
regr_sxy​

Computes the sum of products of paired data points.

regr_sxy(expression_y, expression_x)
Arguments​
  • expression_y: Dependent variable. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression_x: Independent variable. Can be a constant, column, or function, and any combination of arithmetic operators.

Approximate​

approx_distinct​

Returns the approximate number of distinct input values calculated using the HyperLogLog algorithm.

approx_distinct(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
approx_median​

Returns the approximate median (50th percentile) of input values. It is an alias of approx_percentile_cont(x, 0.5).

approx_median(expression)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
approx_percentile_cont​

Returns the approximate percentile of input values using the t-digest algorithm.

approx_percentile_cont(expression, percentile, centroids)
Arguments​

  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.

  • percentile: Percentile to compute. Must be a float value between 0 and 1 (inclusive).

  • centroids: Number of centroids to use in the t-digest algorithm. Default is 100.

    If there are this number or fewer unique values, you can expect an exact result. A higher number of centroids results in a more accurate approximation, but requires more memory to compute.

approx_percentile_cont_with_weight​

Returns the weighted approximate percentile of input values using the t-digest algorithm.

approx_percentile_cont_with_weight(expression, weight, percentile)
Arguments​
  • expression: Expression to operate on. Can be a constant, column, or function, and any combination of arithmetic operators.
  • weight: Expression to use as weight. Can be a constant, column, or function, and any combination of arithmetic operators.
  • percentile: Percentile to compute. Must be a float value between 0 and 1 (inclusive).

Window Functions​

A window function performs a calculation across a set of table rows that are somehow related to the current row. This is comparable to the type of calculation that can be done with an aggregate function. However, window functions do not cause rows to become grouped into a single output row like non-window aggregate calls would. Instead, the rows retain their separate identities. Behind the scenes, the window function is able to access more than just the current row of the query result

Here is an example that shows how to compare each employee's salary with the average salary in his or her department:

SELECT depname, empno, salary, avg(salary) OVER (PARTITION BY depname) FROM empsalary;

+-----------+-------+--------+-------------------+
| depname   | empno | salary | avg               |
+-----------+-------+--------+-------------------+
| personnel | 2     | 3900   | 3700.0            |
| personnel | 5     | 3500   | 3700.0            |
| develop   | 8     | 6000   | 5020.0            |
| develop   | 10    | 5200   | 5020.0            |
| develop   | 11    | 5200   | 5020.0            |
| develop   | 9     | 4500   | 5020.0            |
| develop   | 7     | 4200   | 5020.0            |
| sales     | 1     | 5000   | 4866.666666666667 |
| sales     | 4     | 4800   | 4866.666666666667 |
| sales     | 3     | 4800   | 4866.666666666667 |
+-----------+-------+--------+-------------------+

A window function call always contains an OVER clause directly following the window function's name and argument(s). This is what syntactically distinguishes it from a normal function or non-window aggregate. The OVER clause determines exactly how the rows of the query are split up for processing by the window function. The PARTITION BY clause within OVER divides the rows into groups, or partitions, that share the same values of the PARTITION BY expression(s). For each row, the window function is computed across the rows that fall into the same partition as the current row. The previous example showed how to count the average of a column per partition.

You can also control the order in which rows are processed by window functions using ORDER BY within OVER. (The window ORDER BY does not even have to match the order in which the rows are output.) Here is an example:

SELECT depname, empno, salary,
       rank() OVER (PARTITION BY depname ORDER BY salary DESC)
FROM empsalary;

+-----------+-------+--------+--------+
| depname   | empno | salary | rank   |
+-----------+-------+--------+--------+
| personnel | 2     | 3900   | 1      |
| develop   | 8     | 6000   | 1      |
| develop   | 10    | 5200   | 2      |
| develop   | 11    | 5200   | 2      |
| develop   | 9     | 4500   | 4      |
| develop   | 7     | 4200   | 5      |
| sales     | 1     | 5000   | 1      |
| sales     | 4     | 4800   | 2      |
| personnel | 5     | 3500   | 2      |
| sales     | 3     | 4800   | 2      |
+-----------+-------+--------+--------+

There is another important concept associated with window functions: for each row, there is a set of rows within its partition called its window frame. Some window functions act only on the rows of the window frame, rather than of the whole partition. Here is an example of using window frames in queries:

SELECT depname, empno, salary,
    avg(salary) OVER(ORDER BY salary ASC ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING) AS avg,
    min(salary) OVER(ORDER BY empno ASC ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS cum_min
FROM empsalary
ORDER BY empno ASC;

+-----------+-------+--------+--------------------+---------+
| depname   | empno | salary | avg                | cum_min |
+-----------+-------+--------+--------------------+---------+
| sales     | 1     | 5000   | 5000.0             | 5000    |
| personnel | 2     | 3900   | 3866.6666666666665 | 3900    |
| sales     | 3     | 4800   | 4700.0             | 3900    |
| sales     | 4     | 4800   | 4866.666666666667  | 3900    |
| personnel | 5     | 3500   | 3700.0             | 3500    |
| develop   | 7     | 4200   | 4200.0             | 3500    |
| develop   | 8     | 6000   | 5600.0             | 3500    |
| develop   | 9     | 4500   | 4500.0             | 3500    |
| develop   | 10    | 5200   | 5133.333333333333  | 3500    |
| develop   | 11    | 5200   | 5466.666666666667  | 3500    |
+-----------+-------+--------+--------------------+---------+

When a query involves multiple window functions, it is possible to write out each one with a separate OVER clause, but this is duplicative and error-prone if the same windowing behavior is wanted for several functions. Instead, each windowing behavior can be named in a WINDOW clause and then referenced in OVER. For example:

SELECT sum(salary) OVER w, avg(salary) OVER w
FROM empsalary
WINDOW w AS (PARTITION BY depname ORDER BY salary DESC);

Syntax​

The syntax for the OVER-clause is

function([expr])
  OVER(
    [PARTITION BY expr[, …]]
    [ORDER BY expr [ ASC | DESC ][, …]]
    [ frame_clause ]
    )

where frame_clause is one of:

  { RANGE | ROWS | GROUPS } frame_start
  { RANGE | ROWS | GROUPS } BETWEEN frame_start AND frame_end

and frame_start and frame_end can be one of

UNBOUNDED PRECEDING
offset PRECEDING
CURRENT ROW
offset FOLLOWING
UNBOUNDED FOLLOWING

where offset is an non-negative integer.

RANGE and GROUPS modes require an ORDER BY clause (with RANGE the ORDER BY must specify exactly one column).

Aggregate functions​

All aggregate functions can be used as window functions.

Ranking functions​

row_number​

Number of the current row within its partition, counting from 1.

row_number()
rank​

Rank of the current row with gaps; same as row_number of its first peer.

rank()
dense_rank​

Rank of the current row without gaps; this function counts peer groups.

dense_rank()
ntile​

Integer ranging from 1 to the argument value, dividing the partition as equally as possible.

ntile(expression)
Arguments​
  • expression: An integer describing the number groups the partition should be split into

Analytical functions​

cume_dist​

Relative rank of the current row: (number of rows preceding or peer with current row) / (total rows).

cume_dist()
percent_rank​

Relative rank of the current row: (rank - 1) / (total rows - 1).

percent_rank()
lag​

Returns value evaluated at the row that is offset rows before the current row within the partition; if there is no such row, instead return default (which must be of the same type as value). Both offset and default are evaluated with respect to the current row. If omitted, offset defaults to 1 and default to null.

lag(expression, offset, default)
Arguments​
  • expression: Expression to operate on
  • offset: Integer. Specifies how many rows back the value of expression should be retrieved. Defaults to 1.
  • default: The default value if the offset is not within the partition. Must be of the same type as expression.
lead​

Returns value evaluated at the row that is offset rows after the current row within the partition; if there is no such row, instead return default (which must be of the same type as value). Both offset and default are evaluated with respect to the current row. If omitted, offset defaults to 1 and default to null.

lead(expression, offset, default)
Arguments​
  • expression: Expression to operate on
  • offset: Integer. Specifies how many rows forward the value of expression should be retrieved. Defaults to 1.
  • default: The default value if the offset is not within the partition. Must be of the same type as expression.
first_value​

Returns value evaluated at the row that is the first row of the window frame.

first_value(expression)
Arguments​
  • expression: Expression to operate on
last_value​

Returns value evaluated at the row that is the last row of the window frame.

last_value(expression)
Arguments​
  • expression: Expression to operate on
nth_value​

Returns value evaluated at the row that is the nth row of the window frame (counting from 1); null if no such row.

nth_value(expression, n)
Arguments​
  • expression: The name the column of which nth value to retrieve
  • n: Integer. Specifies the n in nth