SQL string functions

The InfluxDB Clustered SQL implementation supports the following string functions for operating on string values:

• ascii
• bit_length
• btrim
• char_length
• character_length
• concat
• concat_ws
• chr
• ends_with
• find_in_set
• initcap
• instr
• left
• length
• levenshtein
• lower
• lpad
• ltrim
• md5
• octet_length
• overlay
• position
• repeat
• replace
• reverse
• right
• rpad
• rtrim
• split_part
• starts_with
• strpos
• substr
• substr_index
• to_hex
• translate
• trim
• upper
• uuid

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

SELECT DISTINCT
  room,
  ascii(room)::BIGINT AS ascii
FROM home

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

SELECT DISTINCT
  room,
  bit_length(room)::BIGINT AS bit_length
FROM home

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, trim

SELECT DISTINCT
  room,
  btrim(room::STRING, ' Room') AS btrim
FROM home

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 expression to concatenate.

Related functions

contcat_ws

SELECT
  concat('At ', time::STRING, ', the ', room, ' was ', temp::STRING, '°C.') AS concat
FROM home
LIMIT 3

concat_ws

Concatenates multiple strings together with a specified separator.

concat_ws(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 expression to concatenate. Can be a constant, column, or function, and any combination of string operators.

Related functions

concat

SELECT
  concat_ws(' -- ', time::STRING, room, temp::STRING) AS concat_ws
FROM home
LIMIT 3

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

SELECT
  ascii,
  chr(ascii) AS chr
FROM
  (values (112),
          (75),
          (214)
  ) data(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.

SELECT
  string,
  ends_with(string, 'USA') AS ends_with
FROM
  (values ('New York, USA'),
          ('London, UK'),
          ('San Francisco, USA')
  ) data(string)

find_in_set

Returns the position of a string in a comma-delimited list of substrings. Returns 0 if the string is not in the list of substrings.

find_in_set(str, strlist)

Arguments

• str: String expression to find in strlist.
• strlist: A string containing a comma-delimited list of substrings.

SELECT
  string,
  find_in_set(string, 'Isaac,John,Sara') AS find_in_set
FROM
  (values ('John'),
          ('Sarah'),
          ('Isaac')
  ) data(string)

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

SELECT
  string,
  initcap(string) AS initcap
FROM
  (values ('hello world'),
          ('hello-world'),
          ('hello_world')
  ) data(string)

instr

Returns the location where a substring first appears in a string (starting at 1). If the substring is not in the string, the function returns 0.

instr(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.

SELECT
  string,
  instr(string, 'neighbor') AS instr
FROM
  (values ('good neighbor'),
          ('bad neighbor'),
          ('next-door neighbor'),
          ('friend')
  ) data(string)

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

SELECT DISTINCT
  room,
  left(room::STRING, 3) AS left
FROM home

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

SELECT DISTINCT
  room,
  length(room)::BIGINT AS length
FROM home

levenshtein

Returns the Levenshtein distance between two strings.

levenshtein(str1, str2)

Arguments

• str1: First string expression to operate on. Can be a constant, column, or function, and any combination of string operators.
• str2: Second string expression to operate on. Can be a constant, column, or function, and any combination of string operators.

SELECT
  string1,
  string2,
  levenshtein(string1, string2) AS levenshtein
FROM
  (values ('kitten', 'sitting'),
          ('puppy', 'jumping'),
          ('cow', 'lowing')
  ) data(string1, string2)

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

SELECT DISTINCT
  room,
  lower(room::STRING) AS lower
FROM home

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

SELECT DISTINCT
  room,
  lpad(room::STRING, 14, '-') AS lpad
FROM home

ltrim

Removes leading spaces from a string.

ltrim(str)

Arguments

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

Related functions

btrim, rtrim, trim

SELECT
  string,
  ltrim(string) AS ltrim
FROM
  (values ('  Leading spaces'),
          ('Trailing spaces  '),
          ('  Leading and trailing spaces  ')
  ) data(string)

md5

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

md5(str)

Arguments

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

SELECT DISTINCT
  room,
  md5(room) AS md5
FROM home

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

SELECT DISTINCT
  room,
  octet_length(room)::BIGINT AS octet_length
FROM home

overlay

Replaces part of a string with another substring using a specified starting position and number of characters to replace.

overlay(str PLACING substr FROM pos [FOR count])

Arguments

• str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
• substr: Substring to use to replace part of the specified string (str). Can be a constant, column, or function, and any combination of string operators.
• pos: Start position of the substring replacement (substr).
• count: Number of characters in the string (str) to replace with the substring (substr) beginning from the start position (pos). If not specified, the function uses the length of the substring.

SELECT
  string,
  overlay(string PLACING '****' FROM 1 FOR 12) AS overlay
FROM
  (values ('2223000048410010'),
          ('2222420000001113'),
          ('4917484589897107')
  ) data(string)

position

Returns the position of a substring in a string.

position(substr IN str)

Arguments

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

SELECT
  string,
  position('oo' IN string) AS position
FROM
  (values ('cool'),
          ('scoop'),
          ('ice cream')
  ) data(string)

repeat

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

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.

SELECT
  string,
  repeat(string, 3) AS repeat
FROM
  (values ('foo '),
          ('bar '),
          ('baz ')
  ) data(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.

SELECT DISTINCT
  room,
  replace(room::STRING, ' ', '_') AS replace
FROM home

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.

SELECT DISTINCT
  room,
  reverse(room::STRING) AS reverse
FROM home

right

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

SELECT DISTINCT
  room,
  right(room::STRING, 3) AS right
FROM home

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

SELECT DISTINCT
  room,
  rpad(room::STRING, 14, '-') AS rpad
FROM home

rtrim

Removes trailing spaces from a string.

rtrim(str)

Arguments

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

Related functions

btrim, ltrim, trim

SELECT
  string,
  rtrim(string) AS rtrim
FROM
  (values ('  Leading spaces'),
          ('Trailing spaces  '),
          ('  Leading and trailing spaces  ')
  ) data(string)

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.

SELECT
  url,
  split_part(url, '.', 1) AS split_part
FROM
  (values ('www.influxdata.com'),
          ('docs.influxdata.com'),
          ('community.influxdata.com')
  ) data(url)

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.

SELECT DISTINCT
  room,
  starts_with(room::STRING, 'Kit') AS starts_with
FROM home

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.

SELECT DISTINCT
  room,
  strpos(room::STRING, 'Room')::BIGINT AS strpos
FROM home

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.

SELECT DISTINCT
  room,
  substr(room::STRING, 3, 5) AS substr
FROM home

substr_index

Returns the substring that occurs before or after the specified number (count) of delimiter (delimiter) occurrences in a string (str). If the count is positive, the function returns everything to the left of the final delimiter (counting from the left). If the count is negative, the function returns everything to the right of the final delimiter (counting from the right).

substr_index(str, delimiter, count)

Arguments

• str: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
• delimiter: String expression to use to delimit substrings in the string (str). Can be a constant, column, or function, and any combination of string operators.
• count: The Nth occurrence of the delimiter (delimiter) to split on. Can be a constant, column, or function, and any combination of arithmetic operators. Supports positive and negative numbers.

SELECT
  url,
  substr_index(url, '.', 1) AS subdomain,
  substr_index(url, '.', -1) AS tld
FROM
  (values ('docs.influxdata.com'),
          ('community.influxdata.com'),
          ('cloud2.influxdata.com')
  ) data(url)

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.

SELECT DISTINCT
  room,
  translate(room::STRING, 'Rom', 'sOn') AS translate
FROM home

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.

SELECT
  int,
  to_hex(int) AS to_hex
FROM
  (values (123),
          (345),
          (678)
  ) data(int)

trim

Removes leading and trailing spaces from a string.

trim(str)

Arguments

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

Related functions

btrim, ltrim, rtrim

SELECT
  string,
  trim(string) AS trim
FROM
  (values ('  Leading spaces'),
          ('Trailing spaces  '),
          ('  Leading and trailing spaces  ')
  ) data(string)

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

SELECT DISTINCT
  room,
  upper(room::STRING) AS upper
FROM home

uuid

Returns a UUID v4 string value that is unique per row.

uuid()

SELECT
  room,
  uuid() AS uuid
FROM (SELECT DISTINCT room FROM home)