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Elasticsearch Guide [8.1] » SQL » Functions and Operators » String Functions
« Mathematical Functions Type Conversion Functions »

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.

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.

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.

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.

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.

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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