mysql子查询返回错误答案

【问题标题】：mysql subquery returns errormysql子查询返回错误
【发布时间】：2012-03-20 03:10:57
【问题描述】：

SELECT 
    upd.*,
    usr.username AS `username`,
    usr.profile_picture AS `profile_picture`
    ,(
        SELECT COUNT (like.id)
        FROM likes as like
        WHERE upd.update_id = like.item_id
           AND like.uid = 118697835834
    ) as liked_update

FROM updates AS upd
LEFT JOIN users AS usr 
    ON upd.uid = usr.uid
WHERE upd.deleted=0
    AND 
    ( upd.uid=118697835834
        OR EXISTS ( SELECT *
                    FROM   subscribers AS sub 
                    WHERE  upd.uid = sub.suid
                    AND  sub.uid = 118697835834
            )
    )
ORDER BY upd.date DESC
LIMIT 0, 15

SELECT 中的子查询返回以下错误：

You have an error in your SQL syntax; check the manual that corresponds to your MySQL 
    server version for the right syntax to use near 
    'like WHERE upd.update_id = like.item_id AND l' at line 10

【问题讨论】：

标签： php mysql sql join subquery

【解决方案1】：

您不能使用Like 作为别名，它是保留字

SELECT 
    upd.*,
    usr.username AS `username`,
    usr.profile_picture AS `profile_picture`
    ,(
        SELECT COUNT (l.id)
        FROM likes as l
        WHERE upd.update_id = l.item_id
           AND l.uid = 118697835834
    ) as liked_update

FROM updates AS upd
LEFT JOIN users AS usr 
    ON upd.uid = usr.uid
WHERE upd.deleted=0
    AND 
    ( upd.uid=118697835834
        OR EXISTS ( SELECT *
                    FROM   subscribers AS sub 
                    WHERE  upd.uid = sub.suid
                    AND  sub.uid = 118697835834
            )
    )
ORDER BY upd.date DESC
LIMIT 0, 15

【讨论】：

【解决方案2】：

尽量不要在表字段名称或任何其他变量中使用“like”，因为它是 SQL 关键字 - 与 SELECT 或 AND 相同。

【讨论】：

【解决方案3】：

like 是一个保留的 SQL 字

将您的别名更改为 like 或 likeinfo，您的请求就会生效。

【讨论】：

【解决方案4】：

like是SQL中的保留字；您应该为 likes 表使用不同的别名。更改您的子查询：

SELECT
    COUNT (like.id)
FROM
    likes as like
WHERE
    upd.update_id = like.item_id
    AND like.uid = 118697835834

类似于：

SELECT
    COUNT (l.id)
FROM
    likes as l
WHERE
    upd.update_id = l.item_id
    AND l.uid = 118697835834

【讨论】：