NULLIF

Purpose

This function returns the value NULL, if two expressions are identical. Otherwise, the first expression is returned.

Syntax

nullif::=

Usage Notes

The NULLIF function is equivalent to the CASE expression CASE WHEN expr1=expr2 THEN NULL ELSE expr1 END.

Example

SELECT NULLIF(1,2) NULLIF1, NULLIF(1,1) NULLIF2;