如果 MySQL EXPORT_SET() 函数中提供的任何参数为 NULL，则该函数将返回 NULL。以下示例将演示它 -
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)
以上是如果任何参数为 NULL，MySQL EXPORT_SET() 函数返回什么？的详细内容。更多信息请关注PHP中文网其他相关文章！
