存在on子句中的未知列

Question

连接另一个表时遇到问题。

SELECT rank FROM  
    (
        SELECT highscores.playerID, (@rowID := @rowID + 1) AS rank 
        FROM highscores, (SELECT @rowID := 0) r
        JOIN overall ON highscores.playerID = overall.playerID
        WHERE skillID = ?
        ORDER BY skillExperience DESC, highscores.updateTime ASC
    ) data  
WHERE data.playerID = ?

不断告诉我Unknown column 'highscores.playerID' in 'on clause'中存在的Unknown column 'highscores.playerID' in 'on clause' 。 我已经在互联网上寻找该问题的解决方案，但是找不到适合我的解决方案。

是引起问题的行号在这里吗？ 如果可以，我该如何解决这个问题？

Answer 1

您必须首先将highscores表与总体表连接起来：

SELECT rank FROM  
    (
        SELECT highscores.playerID, (@rowID := @rowID + 1) AS rank 
        FROM
          highscores JOIN overall ON highscores.playerID = overall.playerID,
          (SELECT @rowID := 0) r
        WHERE skillID = ?
        ORDER BY skillExperience DESC, highscores.updateTime ASC
    ) data  
WHERE data.playerID = ?

在您的原始查询中，您将派生表r与整体表连接在一起：

(SELECT @rowID := 0) r
JOIN overall ON highscores.playerID = overall.playerID

由于无法找到highscores.playerID，因此无法工作，因为highscores表将被单独连接。