SQL左联接问题（所有行未来）

Question

表列如下：

Users表（表名：Users）：

[用户表]

Friends表（表名：Friends）：

“好友表”

我的Sql代码：

SELECT
    friend_id,
    friend_adding_id,
    friend_added_id,
    user_id,
    user_name
FROM friends
LEFT JOIN users ON friends.friend_added_id = users.user_id
WHERE
    friend_adding_id = 1
    OR friend_added_id = 1
    AND friend_confirm = 1
ORDER BY friends.friend_id DESC
LIMIT 1, 10

留下下面一栏：

“离开栏”

如何修复此缺失的查询？请帮帮我.

Answer 1

首先，您缺少了一行而不是列或者不是查询，其次，这是因为与/或优先级。并且具有比或更高的优先级,要使逻辑正常工作,必须通过使用括号给予或更高的优先级：

SELECT
    friend_id,
    friend_adding_id,
    friend_added_id,
    user_id,
    user_name
FROM friends
LEFT JOIN users ON friends.friend_added_id = users.user_id
WHERE
    (friend_adding_id = 1 OR friend_added_id = 1) -- < like this
    AND friend_confirm = 1
ORDER BY friends.friend_id DESC
LIMIT 1, 10