SELECT USER1.USER_ID, USER1.USER_NAME, USER1.DEPART_ID, DEPART.DEPART_NAME
FROM T_USER_INFO USER1, T_USER_INFO USER2, T_DEPART_INFO DEPART
WHERE (USER1.USER_NAME = USER2.USER_NAME) AND
(USER1.USER_ID <> USER2.USER_ID) AND
(DEPART.DEPART_ID = USER1.DEPART_ID) 运行结果却出现完全重复的记录,这是什么原因啊?
FROM T_USER_INFO USER1, T_USER_INFO USER2, T_DEPART_INFO DEPART
WHERE (USER1.USER_NAME = USER2.USER_NAME) AND
(USER1.USER_ID <> USER2.USER_ID) AND
(DEPART.DEPART_ID = USER1.DEPART_ID) 运行结果却出现完全重复的记录,这是什么原因啊?
SELECT USER1.USER_ID, USER2.USER_NAME, USER1.DEPART_ID, DEPART.DEPART_NAME
FROM T_USER_INFO USER1, T_USER_INFO USER2, T_DEPART_INFO DEPART
WHERE (USER1.USER_NAME = USER2.USER_NAME) AND
(USER1.USER_ID <> USER2.USER_ID) AND
(DEPART.DEPART_ID = USER2.DEPART_ID)
也就是说让结果里包括user1和user2的字段
我没有什么本意,只是看书后自己联系了一下,发现和自己预想的有出入