After this Lab, you will be able to:
The NULLIF and COALESCE functions are defined by the ANSI 1999 standard to be “CASE abbreviations.” Both functions can be used as a variety of the CASE expression.
The NULLIF function compares two expressions. If they are equal, then the function returns NULL; otherwise, it returns the value of the first expression. The NULLIF has the following structure:
NULLIF (expression1, expression2)
If expression1 is equal to expression2, then NULLIF returns NULL. If expression1 does not equal expression2, NULLIF returns expression1. Note that the NULLIF function does the opposite of the NVL ...