ifnull
description
Syntax
ifnull(expr1, expr2)
If the value of expr1 is not null, expr1 is returned, otherwise expr2 is returned
example
mysql> select ifnull(1,0);
+--------------+
| ifnull(1, 0) |
+--------------+
| 1 |
+--------------+
mysql> select ifnull(null,10);
+------------------+
| ifnull(NULL, 10) |
+------------------+
| 10 |
+------------------+keywords
IFNULL