[英]SQL INNER JOIN ON table1.column1 = table2.column2 OR ON ..?
What the SQL script if you want select database by INNER JOIN but with 2 ON and OR between ON. 如果要通过INNER JOIN选择数据库,但使用2 ON和ON之间的OR,则使用什么SQL脚本。
This is my wrong script 这是我的错误脚本
SELECT *
FROM user
INNER JOIN friend ON friend.id1_friend = user.id_user
OR ON friend.id2_friend = user.id_user
WHERE id_user != '$_SESSION[user]'
AND friend_status != '2'
ORDER BY id_user DESC
on is use one time with one table. 一张桌子只能使用一次。 you just put or with other condition.
您刚刚提出的条件或其他条件。
SELECT*FROM user
INNER JOIN friend ON
(friend.id1_friend=user.id_user OR friend.id2_friend=user.id_user)
WHERE id_user != $_SESSION[user]
AND friend_status != '2'
ORDER BY id_user DESC
SELECT * -- this is not smart
FROM user u
JOIN friend f
ON u.id_user IN(f.id1_friend,f.id2_friend)
WHERE u.id_user != '$_SESSION[user]' -- this is not safe
AND f.friend_status != 2
ORDER
BY u.id_user DESC
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