PostgreSQL trim() Function

The PostgreSQL trim() function removes the longest string of specified characters from the start or/and end of the specified string.

`trim()` Syntax

This is the syntax of the PostgreSQL trim() function:

trim([ LEADING | TRAILING | BOTH ] [ characters ] FROM string)

trim([ LEADING | TRAILING | BOTH ] [ FROM ] string [, characters ])

string: Required. The string to trim.
characters: Optional. The characters to remove. The default value is a space.
[ LEADING | TRAILING | BOTH ]: Optional. It indicates where to remove characters. LEADING means to remove characters from the start of the string. TRAILING means to remove characters from the end of the string. BOTH means to remove characters from start and end of the string. The default value is BOTH.

The PostgreSQL trim() function removes the longest string of specified characters from the start or/and end of the specified string.

This example shows how to use trim() to remove spaces from both ends of a string:

SELECT trim(BOTH FROM '    Hello    ');

 btrim
-------
 Hello

This example shows how to use trim() to remove whitespace from the start of a string:

SELECT trim(LEADING FROM '    Hello    ');

   ltrim
-----------
 Hello

This example shows how to use trim() to remove trailing spaces from a string:

SELECT trim(TRAILING FROM '    Hello    ');

   rtrim
-----------
     Hello

This example shows how to remove consecutive specified characters from start and end of a string:

SELECT trim(BOTH '_#' FROM '_#_#_Hello_#_#');

 btrim
-------
 Hello

This example shows how to remove consecutive specified characters from the start of a string:

SELECT trim(LEADING '_#' FROM '_#_#_Hello_#_#');

   ltrim
-----------
 Hello_#_#

This example shows how to remove consecutive specified characters from the end of a string:

SELECT trim(TRAILING '_#' FROM '_#_#_Hello_#_#');

   rtrim
------------
 _#_#_Hello