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String Functions

Functions for performing string manipulation.

`ASCII`

Synopsis:

ASCII(string_exp)

Input:

string expression. If null, the function returns null.

Output: integer

Description: Returns the ASCII code value of the leftmost character of string_exp as an integer.

SELECT ASCII('Elastic');

ASCII('Elastic')
----------------
69

`BIT_LENGTH`

Synopsis:

BIT_LENGTH(string_exp)

Input:

string expression. If null, the function returns null.

Output: integer

Description: Returns the length in bits of the string_exp input expression.

SELECT BIT_LENGTH('Elastic');

BIT_LENGTH('Elastic')
---------------------
56

`CHAR`

Synopsis:

CHAR(code)

Input:

integer expression between 0 and 255. If null, negative, or greater than 255, the function returns null.

Output: string

Description: Returns the character that has the ASCII code value specified by the numeric input.

SELECT CHAR(69);

   CHAR(69)
---------------
E

`CHAR_LENGTH`

Synopsis:

CHAR_LENGTH(string_exp)

Input:

string expression. If null, the function returns null.

Output: integer

Description: Returns the length in characters of the input, if the string expression is of a character data type; otherwise, returns the length in bytes of the string expression (the smallest integer not less than the number of bits divided by 8).

SELECT CHAR_LENGTH('Elastic');

CHAR_LENGTH('Elastic')
----------------------
7

`CONCAT`

Synopsis:

CONCAT(
    string_exp1, 
    string_exp2)

Input:

	string expression. Treats `null` as an empty string.
	string expression. Treats `null` as an empty string.

Output: string

Description: Returns a character string that is the result of concatenating string_exp1 to string_exp2.

The resulting string cannot exceed a byte length of 1 MB.

SELECT CONCAT('Elasticsearch', ' SQL');

CONCAT('Elasticsearch', ' SQL')
-------------------------------
Elasticsearch SQL

`INSERT`

Synopsis:

INSERT(
    source,      
    start,       
    length,      
    replacement)

Input:

	string expression. If `null`, the function returns `null`.
	integer expression. If `null`, the function returns `null`.
	integer expression. If `null`, the function returns `null`.
	string expression. If `null`, the function returns `null`.

Output: string

Description: Returns a string where length characters have been deleted from source, beginning at start, and where replacement has been inserted into source, beginning at start.

The resulting string cannot exceed a byte length of 1 MB.

SELECT INSERT('Elastic ', 8, 1, 'search');

INSERT('Elastic ', 8, 1, 'search')
----------------------------------
Elasticsearch

`LCASE`

Synopsis:

LCASE(string_exp)

Input:

string expression. If null, the function returns null.

Output: string

Description: Returns a string equal to that in string_exp, with all uppercase characters converted to lowercase.

SELECT LCASE('Elastic');

LCASE('Elastic')
----------------
elastic

`LEFT`

Synopsis:

LEFT(
    string_exp, 
    count)

Input:

	string expression. If `null`, the function returns `null`.
	integer expression. If `null`, the function returns `null`. If `0` or negative, the function returns an empty string.

Output: string

Description: Returns the leftmost count characters of string_exp.

SELECT LEFT('Elastic',3);

LEFT('Elastic',3)
-----------------
Ela

`LENGTH`

Synopsis:

LENGTH(string_exp)

Input:

string expression. If null, the function returns null.

Output: integer

Description: Returns the number of characters in string_exp, excluding trailing blanks.

SELECT LENGTH('Elastic   ');

LENGTH('Elastic   ')
--------------------
7

`LOCATE`

Synopsis:

LOCATE(
    pattern, 
    source   
    [, start]
)

Input:

	string expression. If `null`, the function returns `null`.
	string expression. If `null`, the function returns `null`.
	integer expression; optional. If `null`, `0`, `1`, negative, or not specified, the search starts at the first character position.

Output: integer

Description: Returns the starting position of the first occurrence of pattern within source. The optional start specifies the character position to start the search with. If the pattern is not found within source, the function returns 0.

SELECT LOCATE('a', 'Elasticsearch');

LOCATE('a', 'Elasticsearch')
----------------------------
3

SELECT LOCATE('a', 'Elasticsearch', 5);

LOCATE('a', 'Elasticsearch', 5)
-------------------------------
10

`LTRIM`

Synopsis:

LTRIM(string_exp)

Input:

string expression. If null, the function returns null.

Output: string

Description: Returns the characters of string_exp, with leading blanks removed.

SELECT LTRIM('   Elastic');

LTRIM('   Elastic')
-------------------
Elastic

`OCTET_LENGTH`

Synopsis:

OCTET_LENGTH(string_exp)

Input:

string expression. If null, the function returns null.

Output: integer

Description: Returns the length in bytes of the string_exp input expression.

SELECT OCTET_LENGTH('Elastic');

OCTET_LENGTH('Elastic')
-----------------------
7

`POSITION`

Synopsis:

POSITION(
    string_exp1, 
    string_exp2)

Input:

	string expression. If `null`, the function returns `null`.
	string expression. If `null`, the function returns `null`.

Output: integer

Description: Returns the position of the string_exp1 in string_exp2. The result is an exact numeric.

SELECT POSITION('Elastic', 'Elasticsearch');

POSITION('Elastic', 'Elasticsearch')
------------------------------------
1

`REPEAT`

Synopsis:

REPEAT(
    string_exp, 
    count)

Input:

	string expression. If `null`, the function returns `null`.
	integer expression. If `0`, negative, or `null`, the function returns `null`.

Output: string

Description: Returns a character string composed of string_exp repeated count times.

The resulting string cannot exceed a byte length of 1 MB.

SELECT REPEAT('La', 3);

 REPEAT('La', 3)
----------------
LaLaLa

`REPLACE`

Synopsis:

REPLACE(
    source,      
    pattern,     
    replacement)

Input:

	string expression. If `null`, the function returns `null`.
	string expression. If `null`, the function returns `null`.
	string expression. If `null`, the function returns `null`.

Output: string

Description: Search source for occurrences of pattern, and replace with replacement.

The resulting string cannot exceed a byte length of 1 MB.

SELECT REPLACE('Elastic','El','Fant');

REPLACE('Elastic','El','Fant')
------------------------------
Fantastic

`RIGHT`

Synopsis:

RIGHT(
    string_exp, 
    count)

Input:

	string expression. If `null`, the function returns `null`.
	integer expression. If `null`, the function returns `null`. If `0` or negative, the function returns an empty string.

Output: string

Description: Returns the rightmost count characters of string_exp.

SELECT RIGHT('Elastic',3);

RIGHT('Elastic',3)
------------------
tic

`RTRIM`

Synopsis:

RTRIM(string_exp)

Input:

string expression. If null, the function returns null.

Output: string

Description: Returns the characters of string_exp with trailing blanks removed.

SELECT RTRIM('Elastic   ');

RTRIM('Elastic   ')
-------------------
Elastic

`SPACE`

Synopsis:

SPACE(count)

Input:

integer expression. If null or negative, the function returns null.

Output: string

Description: Returns a character string consisting of count spaces.

The resulting string cannot exceed a byte length of 1 MB.

SELECT SPACE(3);

   SPACE(3)
---------------

`STARTS_WITH`

Synopsis:

STARTS_WITH(
    source,   
    pattern)

Input:

	string expression. If `null`, the function returns `null`.
	string expression. If `null`, the function returns `null`.

Output: boolean value

Description: Returns true if the source expression starts with the specified pattern, false otherwise. The matching is case sensitive.

SELECT STARTS_WITH('Elasticsearch', 'Elastic');

STARTS_WITH('Elasticsearch', 'Elastic')
--------------------------------
true

SELECT STARTS_WITH('Elasticsearch', 'ELASTIC');

STARTS_WITH('Elasticsearch', 'ELASTIC')
--------------------------------
false

`SUBSTRING`

Synopsis:

SUBSTRING(
    source, 
    start,  
    length)

Input:

	string expression. If `null`, the function returns `null`.
	integer expression. If `null`, the function returns `null`.
	integer expression. If `null`, the function returns `null`.

Output: string

Description: Returns a character string that is derived from source, beginning at the character position specified by start for length characters.

SELECT SUBSTRING('Elasticsearch', 0, 7);

SUBSTRING('Elasticsearch', 0, 7)
--------------------------------
Elastic

`TRIM`

Synopsis:

TRIM(string_exp)

Input:

string expression. If null, the function returns null.

Output: string

Description: Returns the characters of string_exp, with leading and trailing blanks removed.

SELECT TRIM('   Elastic   ') AS trimmed;

trimmed
--------------
Elastic

`UCASE`

Synopsis:

UCASE(string_exp)

Input:

string expression. If null, the function returns null.

Output: string

Description: Returns a string equal to that of the input, with all lowercase characters converted to uppercase.

SELECT UCASE('Elastic');

UCASE('Elastic')
----------------
ELASTIC

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https://www.elastic.co/guide/en/elasticsearch/reference/8.17/sql-functions-string.html