Oracle / PLSQL: NULLIF Function

This article is written about how to use the Oracle/PLSQL NULLIF function with syntax and examples.

Description

The Oracle/PLSQL NULLIF function compares expr1 and expr2. If expr1 and expr2 are equal, the NULLIF function returns NULL. Otherwise, it returns expr1.

Syntax

The syntax for the NULLIF function in Oracle/PLSQL is:

NULLIF( expr1, expr2 )

Parameters or Arguments

expr1

First value to compare. Must be either a numeric value or a value that is the same datatype as expr2.

expr2

Second value to compare. Must be either a numeric value or a value that is the same datatype as expr1.

Returns

The NULLIF function returns NULL if expr1 and expr2 are equal.

The NULLIF function returns expr1 if expr1 and expr2 are not equal.

Note

expr1 can be an expression that evaluates to NULL, but it can not be the literal NULL.

Applies To

The NULLIF function can be used in the following versions of Oracle/PLSQL:

Oracle 12c, Oracle 11g, Oracle 10g, Oracle 9i

Example

Let’s look at some Oracle NULLIF function examples and explore how to use the NULLIF function in Oracle/PLSQL.

For example:

NULLIF(12, 12)
Result: NULL

NULLIF(12, 13)
Result: 12

NULLIF('apples', 'apples')
Result: NULL

NULLIF('apples', 'oranges')
Result: 'apples'

NULLIF(NULL, 12)
Result: ORA-00932 error   (because expr1 can not be the literal NULL)