ltrim
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ltrim
Library: ib_udf
Changed in: 1.5, 1.5.2, 2.0
Better alternative: Internal function TRIM()
Description
Returns the input string with any leading space characters removed. In new code, you are advised to use the internal function TRIM()
instead, as it is both more powerful and more versatile.
Result type: VARCHAR(n)
Syntax (unchanged)
ltrim (str)
Declaration
DECLARE EXTERNAL FUNCTION ltrim CSTRING(255) NULL RETURNS CSTRING(255) FREE_IT ENTRY_POINT 'IB_UDF_ltrim' MODULE_NAME 'ib_udf'
The above declaration is from the file ib_udf2.sql
. The NULL
after the argument is an optional addition that became available in Firebird 2. If the argument is declared with the NULL
keyword, the engine will pass a NULL
argument value unchanged to the function. This leads to a NULL
result, which is correct. Without the NULL
keyword (your only option in pre-2.0 versions), NULL
is passed to the function as an empty string and the result is an empty string as well.
For more information about passing NULL
s to UDFs, see the note at the end of this book.
Notes:
- Depending on how you declare it (see
CSTRING
note), this function can accept and return strings of up to 32767 characters. - Before Firebird 2.0, the result type was
CHAR(n)
. - In Firebird 1.5.1 and below, the default declaration used
CSTRING(80)
instead ofCSTRING(255)
. - In Firebird 1.0.x, this function returned
NULL
if the input string was either empty orNULL
.
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