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Updated on 2023-10-25 GMT+08:00
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ltrim

This function is used to remove characters from the left of str.

  • If trimChars is not specified, spaces are removed by default.
  • If trimChars is specified, the function removes the longest possible substring from the left end of str that consists of characters in the trimChars set.

Similar functions:

  • rtrim. This function is used to remove characters from the right of str.
  • trim. This function is used to remove characters from the left and right of str.

Syntax

ltrim([<trimChars>,] string <str>)

Parameters

Table 1 Parameters

Parameter

Mandatory

Type

Description

str

Yes

STRING

String from which characters on the left are to be removed. If the value is of the BIGINT, DECIMAL, DOUBLE, or DATETIME type, the value is implicitly converted to the STRING type for calculation.

trimChars

Yes

STRING

Characters to be removed

Return Values

The return value is of the STRING type.

  • If the value of str is not of the STRING, BIGINT, DOUBLE, DECIMAL, or DATETIME type, an error is reported.
  • If the value of str or trimChars is NULL, NULL is returned.

Example Code

  • Removes spaces on the left of string abc. An example command is as follows:

    The value stringabc is returned.

    select ltrim('     abc');

    It is equivalent to the following statement:

    select trim(leading from '     abc');

    leading indicates that the leading spaces in a string are removed.

  • The value of the input parameter is NULL. An example command is as follows:

    The value NULL is returned.

    select ltrim(null); 
select ltrim('xy', null);
select ltrim(null, 'xy');
  • Removes all substrings from the left end of the string yxlucyxx that consist of characters in the set xy.

    The function returns lucyxx, as any substring starting with x or y from the left end is removed.

    select ltrim( 'xy','yxlucyxx');

    It is equivalent to the following statement:

    select trim(leading 'xy' from 'yxlucyxx');
Parent topic: String Functions