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Oracle/PLSQL: NULLIF Function

Learn how to use the Oracle/PLSQL NULLIF function with syntax and examples.


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


The syntax for the Oracle/PLSQL NULLIF function is:

NULLIF( expr1, expr2 )

Parameters or Arguments

expr1 and expr2 must be either numeric values or values that are of the same datatype.


  • 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


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'

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