Library: fbudf
Added in: 1.0 (Win), 1.5 (Linux)
Better alternative: Internal function NULLIF()
Description
The four *nullif functions – for integers, bigints, doubles and strings, respectively – each return the first argument if it is not equal to the second. If the arguments are equal, the functions return NULL.
Result type: Varies, see declarations.
Syntax
inullif (int1, int2) i64nullif (bigint1, bigint2) dnullif (double1, double2) snullif (string1, string2)
As from Firebird 1.5 use of the internal function NULLIF() is preferred.
Warnings:
Declarations
DECLARE EXTERNAL FUNCTION inullif INT BY DESCRIPTOR, INT BY DESCRIPTOR RETURNS INT BY DESCRIPTOR ENTRY_POINT 'iNullIf' MODULE_NAME 'fbudf' DECLARE EXTERNAL FUNCTION i64nullif NUMERIC(18,4) BY DESCRIPTOR, NUMERIC(18,4) BY DESCRIPTOR RETURNS NUMERIC(18,4) BY DESCRIPTOR ENTRY_POINT 'iNullIf' MODULE_NAME 'fbudf' DECLARE EXTERNAL FUNCTION dnullif DOUBLE PRECISION BY DESCRIPTOR, DOUBLE PRECISION BY DESCRIPTOR RETURNS DOUBLE PRECISION BY DESCRIPTOR ENTRY_POINT 'dNullIf' MODULE_NAME 'fbudf' DECLARE EXTERNAL FUNCTION snullif VARCHAR(100) BY DESCRIPTOR, VARCHAR(100) BY DESCRIPTOR, VARCHAR(100) BY DESCRIPTOR RETURNS PARAMETER 3 ENTRY_POINT 'sNullIf' MODULE_NAME 'fbudf'