PostgreSQL – LTRIM Function
The ltrim
function is used to remove characters from the left end (beginning) of a string. It takes two arguments: the input string and a list of characters to be removed from the left side of the input string.
Here’s the syntax for the ltrim
function:
ltrim(input_string, characters_to_remove)
where
input_string
is the string from which you want to remove characters from the left side.characters_to_remove
(optional) is a string containing the characters you want to remove from the left side of the input string. If you do not provide a string, ltrim function will remove the nulls from the left side.
The ltrim
function will return a new string with all leading characters from the characters_to_remove
list removed from the left side of the input string.
Here’s an example of how to use the ltrim
function:
SELECT ltrim('Hello, world!', 'H');
In this example, the ltrim
function is used to remove ‘H’ from the left side of the string 'Hello, world!'
. The result of this query will be 'ello, world!'
because it removed the leading ‘H’.
You can use any list of characters in the characters_to_remove
argument, and ltrim
will remove all occurrences of those characters from the left side of the input string until it encounters a character that is not in the list.
LTRIM function can be used to remove the leading null characters as below:
SELECT ltrim(' Hello, world!', ' '); -- removes leading nulls
or
SELECT ltrim(' Hello, world!'); -- removes leading nulls