Categories:

String & binary functions (General)

LTRIM¶

Removes leading characters, including whitespace, from a string.

Note

To remove characters in a string, you can use the REPLACE function.

See also:

RTRIM , TRIM

Syntax¶

LTRIM( <expr> [, <characters> ] )
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Arguments¶

expr

The string expression to be trimmed.

characters

One or more characters to remove from the left side of expr.

The default value is ' ' (a single blank space character). If no characters are specified, only blank spaces are removed.

Returns¶

This function returns a value of VARCHAR data type or NULL. If either argument is NULL, returns NULL.

Usage notes¶

  • You can specify the characters in characters in any order.

  • A specification of ' ' in characters does not remove other whitespace characters (such as tabulation characters, end-of-line characters, and so on). Explicitly specify these characters to remove them.

  • When characters is specified, you must explicitly specify the characters to remove whitespace. For example, ' $.' removes all leading blank spaces, dollar signs, and periods from the input string.

Collation details¶

Collation is supported when the optional second argument is omitted, or when it contains only whitespace.

The collation specification of the returned value is the same as the collation specification of the first argument.

Examples¶

Remove leading 0 and # characters from a string:

SELECT LTRIM('#000000123', '0#');
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+---------------------------+
| LTRIM('#000000123', '0#') |
|---------------------------|
| 123                       |
+---------------------------+

The remaining examples use the following table data. Also, the queries enclose the strings in > and < characters to help you visualize the whitespace.

CREATE OR REPLACE TABLE test_ltrim_function(column1 VARCHAR);

INSERT INTO test_ltrim_function VALUES ('  #Leading Spaces');
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Remove leading whitespace from a string. This example does not specify the second characters argument because the default is blank spaces.

SELECT CONCAT('>', CONCAT(column1, '<')) AS original_value,
       CONCAT('>', CONCAT(LTRIM(column1), '<')) AS trimmed_value
  FROM test_ltrim_function;
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+---------------------+-------------------+
| ORIGINAL_VALUE      | TRIMMED_VALUE     |
|---------------------+-------------------|
| >  #Leading Spaces< | >#Leading Spaces< |
+---------------------+-------------------+

Remove leading whitespace and # from a string. This example specifies the second characters argument because it removes other characters in addition to blank spaces.

SELECT CONCAT('>', CONCAT(column1, '<')) AS original_value,
       CONCAT('>', CONCAT(LTRIM(column1, ' #'), '<')) AS trimmed_value
  FROM test_ltrim_function;
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+---------------------+------------------+
| ORIGINAL_VALUE      | TRIMMED_VALUE    |
|---------------------+------------------|
| >  #Leading Spaces< | >Leading Spaces< |
+---------------------+------------------+
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