COALESCE
Description
Returns the first non-null expression from left to right in the parameter list. If all arguments are NULL, returns NULL.
Syntax
COALESCE(<expr> [, ...])
Parameters
| Parameter | Description |
|---|---|
<expr> | A sequence of expressions to evaluate. All expressions must be compatible data types. |
Return Value
The first non-null expression in the parameter list. Returns NULL if all arguments are NULL.
Examples
SELECT COALESCE(NULL, '1111', '0000');
+--------------------------------+
| coalesce(NULL, '1111', '0000') |
+--------------------------------+
| 1111 |
+--------------------------------+
