内部联接上有很多帖子,但不确定是否能完全解决我的问题?
我有四个要联接的表,前三个表似乎正确,当我联接第四个表时,联接乘以行(表AB *表C)。
第四张表只有37行,但是根据viewunitsonrun.strUnitCode需要将每一行专门插入几次,并在第一张表中重复几次(tblawardedlearers)。
SELECT viewlearnersonrun.intRunID,
intlearnerID,
strFirstname,
strunitcode,
strGrade
FROM tblawardedlearners
INNER JOIN viewlearnersonrun
ON viewlearnersonrun.intID = tblawardedlearners.intLearnerID
INNER JOIN viewrun
ON viewrun.intID = viewlearnersonrun.intRunID /*CORRECT TO THIS POINT */
INNER JOIN viewunitsonrun
ON viewunitsonrun.strUnitCode = tblawardedlearners.strUnitCode
WHERE viewlearnersonrun.intRunID = '200GE2' /* display only one Course */
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