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NULLIF

Returns NULL if the arguments are equal, otherwise the first argument.

Syntax

NULLIF (val1, val2)

Arguments

  • Any SQL objects

Return Type

The return value has the same type as the first argument, or NULL.

Examples

select nullif(1,2);
+-------------+
| nullif(1,2) |
+-------------+
|           1 |
+-------------+

select nullif(2,2);
+-------------+
| nullif(2,2) |
+-------------+
|        NULL |
+-------------+

select nullif(NULL, NULL);
+--------------------+
| nullif(NULL, NULL) |
+--------------------+
| NULL               |
+--------------------+

select NULL = NULL;
+-------------+
| NULL = NULL |
+-------------+
|        NULL |
+-------------+