Introduction to PostgreSQL LTRIM() function

TheLTRIM() function allows you to remove specified characters from the beginning of a string.

Here’s the syntax of theLTRIM() function:

LTRIM(string,character)

In this syntax:

• string is the input string that you want to remove characters.
• character specifies the characters you want to remove from the beginning of thestring. Thecharacter parameter is optional. It defaults to space.

TheLTRIM() function returns the string with all leading characters removed.

To remove both leading and trailing characters from a string, you use theTRIM() function.

To remove the trailing characters from a string, you use theRTRIM() function.

PostgreSQL LTRIM() function examples

Let’s explore some examples of using theLTRIM() function.

1) Basic PostgreSQL LTRIM() function example

The following example uses theLTRIM() function to remove the# from the beginning of the string#postgres:

SELECT LTRIM('#postgres','#');

Output:

ltrim---------- postgres(1 row)

2) Using the PostgreSQL LTRIM() function to remove leading spaces

The following example uses theLTRIM() function to remove all the spaces from the string' PostgreSQL':

SELECT LTRIM('   PostgreSQL');

Output:

ltrim------------ PostgreSQL(1 row)

Since the default of the second argument of theLTRIM() function is space, we don’t need to specify it.

3) Using the LTRIM() function with table data example

First,create a new table calledarticles andinsert some rows into it:

CREATE TABLE articles(   idSERIAL PRIMARY KEY,   titleVARCHAR(255)NOT NULL);INSERT INTO articles(title)VALUES   ('   Mastering PostgreSQL string functions'),   (' PostgreSQL LTRIM() function')RETURNING*;

Output:

id |                  title----+------------------------------------------  1 |    Mastering PostgreSQL string functions  2 |  PostgreSQL LTRIM() function(2 rows)

Second,update the titles by removing the leading spaces using theLTRIM() function:

UPDATE articlesSET title= LTRIM(title);

Output:

UPDATE 2

The output indicates that two rows were updated.

Third, verify the updates:

SELECT * FROM articles;

Output:

id |                 title----+---------------------------------------  1 | Mastering PostgreSQL string functions  2 | PostgreSQL LTRIM() function(2 rows)

Summary

• UseLTRIM() function to remove all specified characters from the beginning of a string.

Last updated onJanuary 27, 2024

On this page

• Introduction to PostgreSQL LTRIM() function
• PostgreSQL LTRIM() function examples
• Summary