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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 you would use the NULLIF function in Oracle/PLSQL.

For example:

NULLIF(12, 12) would return NULL
NULLIF(12, 13) would return 12
NULLIF('apples', 'apples') would return NULL
NULLIF('apples', 'oranges') would return 'apples'
NULLIF(NULL, 12) would return an ORA-00932 error because
expr1 can not be the literal NULL