PostgreSQL ltrim() Function

The PostgreSQL ltrim() function removes the longest string containing only characters specified by the argument (space by default) from the start of a string.

You can also use rtrim() to remove specified characters from the end of a string, or use btrim() to remove specified characters from both ends of a string.

ltrim() Syntax

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

ltrim(text)

or

ltrim(text, characters)

Parameters

text

Required. The string to remove characters.

characters

Optional. The string containing the characters to remove. The default is a space.

Return value

The PostgreSQL ltrim() function removes the longest string containing only characters specified by the argument (one space by default) from the start of a string, and returns the string.

ltrim() Examples

SELECT
    length(ltrim('a  ')) AS "length(ltrim('a  '))",
    length(ltrim('  a')) AS "length(ltrim('  a'))",
    length(ltrim(' a ')) AS "length(ltrim(' a '))";

 length(ltrim('a  ')) | length(ltrim('  a')) | length(ltrim(' a '))
----------------------+----------------------+----------------------
                    3 |                    1 |                    2

Here:

  • We’ve only used one parameter, then ltrim() will remove spaces from start of the string.
  • To make the result look more intuitive, we use length() function to display length of the returned string.

Let’s use ltrim() to remove specified characters from start of a string:

SELECT ltrim('xxyHELLOzxy', 'xyz') AS "ltrim('xxyHELLOzxy', 'xyz')";

 ltrim('xxyHELLOzxy', 'xyz')
-----------------------------
 HELLOzxy