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我有以下查询，它连接多个表，每个表包含超过 100 万行：

Select * From TableA A
LEFT JOIN TableB B ON A.col1 = B.col1 
INNER JOIN TableC C ON C.col2 = B.col2
INNER JOIN TableD D ON D.col2 = C.col2
INNER JOIN TableE E ON E.col1 = B.col1 
INNER JOIN (Select * From TableF F JOIN TableG G ON F.ID=G.ID) FG 
                          ON  FG.cId = E.cId AND FG.custID = C.custID
WHERE C.ACCEPTED = 'Y'
AND D.colx IS NULL
AND D.coly IS NULL 
And D.START_DATE <= A.SD
And D.END_DATE >= A.SD

由于这花费了太长时间，我决定对其进行优化并提出以下建议：

Select * From TableA A
INNER JOIN TableE E ON E.col1 = A.col1 
INNER JOIN (Select * From TableF F JOIN TableG G ON F.ID=G.ID) FG 
                              ON FG.cID = C.cID AND  FG.custID = 
                                              (Select custID From 
                                   TableB B 
                                   TableC C ON C.col2 = B.col2
                                   TableD D ON D.col2 = C.col2
                                   WHERE C.ACCEPTED = 'Y'
                                   AND D.colx IS NULL
                                   AND D.colx IS NULL 
                                   And D.START_DATE <=  A.SD
                                   And D.END_DATE >=  A.SD
                                   AND B.col1 = A.col1                                                 
                                   AND rownum = 1
                                  )

这改进了查询，但我不确定这两个查询是否会产生相同的结果（我已经测试了一些场景，结果似乎相同，但由于所有表都包含数百万行，我无法遍历每一行并进行比较），而不是像我在第二个中那样简单地从子查询中获取 custId 来加入所有这些表是正确的吗？

谢谢

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