谁能告诉我以null为值的记录如何去查找????
表格为Group_1 2 3 都为int(11)
+---------+---------+---------+
¦ Group_1 ¦ Group_2 ¦ Group_3 ¦
+---------+---------+---------+
¦ 10001 ¦ 10002 ¦ 10003 ¦
¦ NULL ¦ NULL ¦ 10006 ¦
+---------+---------+---------+
怎么select ,才能列出以null为值的记录.