Question

我在SQL Server数据库中有三个表：Submission，Quote和Company。 Submission：Quote和Company：Quote的外键关系为1：n，即报价属于一个提交和一个公司。我有一个查询，为那些具有指定公司至少一个报价的提交选择所有报价：

SELECT *
FROM Submission S, Quote Q, Company C
WHERE Q.submissionId = S.submissionId AND
    Q.companyId = C.companyId AND
    EXISTS (
        SELECT *
        FROM Quote T
        WHERE T.submissionId = S.submissionId AND
            T.companyId = @companyId
    )
ORDER BY S.legalName

是否有更高效和/或更简洁的方式来完成我在这里所做的事情？我无法摆脱应有的感觉。

Answer 1

SELECT *
FROM Submission S
INNER JOIN Quote Q   ON Q.submissionId = S.submissionId
INNER JOIN Company C ON Q.companyId = C.companyId 
WHERE  Q.companyId = @companyId
ORDER BY S.legalName

修改

SELECT *
FROM Submission S
INNER JOIN Quote Q   ON Q.submissionId = S.submissionId
INNER JOIN Company C ON Q.companyId = C.companyId 
WHERE  EXISTS (SELECT 1 
               FROM Submission Sub
               INNER JOIN Quote Qt  ON Qt.submissionId = Sub.submissionId
               WHERE Sub.submissionId = S.submissionId
                AND  Qt.companyId = @companyId)
ORDER BY S.legalName

Answer 2

加入子选择语句以获取特定的提交者。

SELECT * 
FROM Submission S 
INNER JOIN Quote Q 
        ON Q.submissionId = S.submissionId
INNER JOIN Company C 
        ON Q.companyId =C.companyId  
INNER JOIN (SELECT DISTINCT qt.submissionId 
            FROM Quote qt 
            WHERE qt.companyId = @companyId) Q2
        ON Q2.submissionId = S.submissionId
ORDER BY S.legalName

使用＆＃34;至少一个＆＃34;选择记录条件1：n外键关系

2 个答案:

修改