Oracle NULLIF function

Preamble

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

Oracle/PLSQL syntax of the function NULLIF

NULLIF( expr1_id, expr2_id )

Parameters or arguments

• expr1_id and expr2_id must either have numerical values or values that have the same data type.

Note:

• The function NULLIF returns NULL if expr1_id and expr2_id are equal.
• The function NULLIF returns expr1 if expr1_id and expr2_id are not equal.
• expr1 can be an expression which is evaluated as NULL but cannot be literal NULL.

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

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

 

Let’s consider some examples of Oracle NULLIF function and learn how to use NULLIF function in Oracle PLSQL.

SELECT NULLIF(12, 12) AS RESULT FROM DUAL;

-result: NULL

SELECT NULLIF(12, 13) AS RESULT FROM DUAL;

-result: 12

SELECT NULLIF('apples', 'apples') AS RESULT FROM DUAL;

-RESULT: NULL

SELECT NULLIF('apples', 'oranges') AS RESULT FROM DUAL;

-RESULT: apples

SELECT NULLIF(NULL, 12) AS RESULT FROM DUAL;
SELECT NULLIF(NULL, 12) AS RESULT FROM DUAL
ORA-00932: inconsistent datatypes: expected - got CHAR
-- ORA-00932 error because expr1 can't be literal NULL

NULLIF FUNCTION IN ORACLE SQL WITH EXAMPLE

 

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