EXPORT_SET() ফাংশনে যেকোনো আর্গুমেন্ট NULL হলে কী ফেরত দেয়?

EXPORT_SET() ফাংশনের যেকোনো আর্গুমেন্ট NULL থাকলে MySQL NULL ফেরত দেয়।

উদাহরণ

mysql> SELECT EXPORT_SET(NULL, 'Y', 'N', ',', 4);
+----------------------------------+
| EXPORT_SET(NULL, 'Y', 'N', ',', 4) |
+----------------------------------+
| NULL                             |
+----------------------------------+
1 row in set (0.00 sec)

mysql> SELECT EXPORT_SET(5, NULL, 'N', ',', 4);
+--------------------------------+
| EXPORT_SET(5, NULL, 'N', ',', 4) |
+--------------------------------+
| NULL                           |
+--------------------------------+
1 row in set (0.00 sec)

mysql> SELECT EXPORT_SET(5, 'Y', 'N', ',', NULL);
+----------------------------------+
| EXPORT_SET(5, 'Y', 'N', ',', NULL) |
+----------------------------------+
| NULL                             |
+----------------------------------+
1 row in set (0.00 sec)

mysql> SELECT EXPORT_SET(5, 'Y', 'N', NULL, 4);
+--------------------------------+
| EXPORT_SET(5, 'Y', 'N', NULL, 4) |
+--------------------------------+
| NULL                           |
+--------------------------------+
1 row in set (0.00 sec)