Categories:: Conditional expression functions

NULLIF¶

Returns NULL if expr1 is equal to expr2, otherwise returns expr1.

Syntax¶

NULLIF( <expr1> , <expr2> )

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Arguments¶

expr1: Any general expression of any data type.
expr2: Any general expression that evaluates to the same data type as expr1.

Returns¶

The data type of the returned value is the data type of expr1.

Collation details¶

The collation specifications of all input arguments must be compatible.
The collation of the result is the same as the collation of the first input.

Examples¶

SELECT a, b, NULLIF(a,b) FROM i;

--------+--------+-------------+
   a    |   b    | nullif(a,b) |
--------+--------+-------------+
 0      | 0      | [NULL]      |
 0      | 1      | 0           |
 0      | [NULL] | 0           |
 1      | 0      | 1           |
 1      | 1      | [NULL]      |
 1      | [NULL] | 1           |
 [NULL] | 0      | [NULL]      |
 [NULL] | 1      | [NULL]      |
 [NULL] | [NULL] | [NULL]      |
--------+--------+-------------+

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