IFNULL

The IFNULL() function return the first expression if it is not NULL. Otherwise, the second expression is returned.

Syntax

IFNULL( <expr1>, <expr2>)

Arguments

Arguments	Description
<expr1>	Any general expression of any data type.
<expr2>	Any general expression that evaluates to the same data type as <expr1>.

Return Type

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

Examples

SELECT a, b, IFNULL(a, b) FROM t;
+------+------+--------------+
| a    | b    | IFNULL(a, b) |
+------+------+--------------+
|    0 |    1 |            0 |
|    0 | NULL |            0 |
| NULL |    1 |            1 |
| NULL | NULL |         NULL |
+------+------+--------------+