NULLIF

Compare two expressions and return NULL if they are equal. If the expressions differ, the function returns the first expression.

Syntax

NULLIF(expr1,expr2)

Description

Returns NULL if expr1 = expr2 is true, otherwise returns expr1. This is the same as CASE WHEN expr1 = expr2 THEN NULL ELSE expr1 END.

Examples

SELECT NULLIF(1,1);
+-------------+
| NULLIF(1,1) |
+-------------+
|        NULL |
+-------------+

SELECT NULLIF(1,2);
+-------------+
| NULLIF(1,2) |
+-------------+
|           1 |
+-------------+

See Also

• NULL values

• IS NULL operator

• IS NOT NULL operator

• COALESCE function

• IFNULL function

• CONNECT data types

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