Mysql 查询条件的格式

下面的代码是查询的一部分。我似乎对代码中的

部分和C2.loginid=S2.loginid

部分的格式有误。我应该使用什么格式

提前感谢,

约翰

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和ON C2.loginid=S2.loginid

==>在

和

LEFT JOIN (
    SELECT S2.loginid, COUNT(1) AS total 
    FROM submission S2
    INNER JOIN comment C2
    ON C2.submissionid = S2.submissionid
      AND C2.loginid = S2.loginid
    GROUP BY S2.loginid
) scs ON scs.loginid = l.loginid

LEFT JOIN (
    SELECT S2.loginid, COUNT(1) AS total 
    FROM submission S2
    INNER JOIN comment C2
    ON C2.submissionid = S2.submissionid
      AND C2.loginid = S2.loginid
    GROUP BY S2.loginid
) scs ON scs.loginid = l.loginid