Using CONCAT_WS with NULL value : CONCAT_WS « String Functions « MySQL Tutorial

1. MySQL Tutorial
2. String Functions
3. CONCAT_WS

mysql>
mysql>
mysql> SELECT CONCAT_WS(',','First name',NULL,'Last Name');
+----------------------------------------------+
| CONCAT_WS(',','First name',NULL,'Last Name') |
+----------------------------------------------+
| First name,Last Name                         |
+----------------------------------------------+
1 row in set (0.00 sec)

mysql>