coalesce
Description
Syntax:
coalesce(expr1, expr2, ...., expr_n)
This function returns the first non-empty expression in the arguments (from left to right).
Example
mysql> select coalesce(NULL, '1111', '0000');
+--------------------------------+
| coalesce(NULL, '1111', '0000') |
+--------------------------------+
| 1111 |
+--------------------------------+Keywords
COALESCE