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我有一个运行良好的 Select 语句，产生 7636 行： 

SELECT c.ClientId
    FROM   dbo.tblTreatment e
      JOIN dbo.tblProgramAssessment pa
    ON pa.TreatmentID = e.TreatmentId
      JOIN #Client c
    ON c.ClientId = e.ClientId
      LEFT JOIN dbo.tblCessationOfTreatment ct
    ON ct.TreatmentId = e.TreatmentId
      LEFT JOIN dbo.tblClientGP m
    ON m.ClientId = c.ClientId
    WHERE  e.IsOpen = 1 
    AND    e.IsDeleted = 0 
    AND    ct.CessationDate is null
    AND    c.IsDeceased = 0

我正在尝试更新这 7636 行，但它改为更新 7446 行。在我（有限的）理解中，这可能是由于 clientid 的某种原因。这是更新声明：

UPDATE 
    #Client
SET 
    ToMigrate = 1
    , OpenTreatmentEpisodes = 1
WHERE 
    clientid in
    (SELECT c.ClientId
    FROM   dbo.tblTreatment e
      JOIN dbo.tblProgramAssessment pa
    ON pa.TreatmentID = e.TreatmentId
      JOIN #Client c
    ON c.ClientId = e.ClientId
      LEFT JOIN dbo.tblCessationOfTreatment ct
    ON ct.TreatmentId = e.TreatmentId
      LEFT JOIN dbo.tblClientGP m
    ON m.ClientId = c.ClientId
    WHERE  e.IsOpen = 1 
    AND    e.IsDeleted = 0 
    AND    ct.CessationDate is null
    AND    c.IsDeceased = 0  
)

如果我将“IN”更改为“=”，我会收到一条错误消息：子查询返回超过 1 个值。当子查询跟随 =、!=、<、<=、>、>= 或子查询用作表达式时，这是不允许的。该语句已终止。

1）我真的不明白为什么 7446 和 7636 行有区别。2) 我怎样才能只更新 select 语句中的 7636 行？

先感谢您！

4

1 回答 1

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正如尼克评论的那样，您可能clientid在 table中重复了#Client。结果，您的子查询返回的某些元素IN与外部查询中的几行匹配，从而导致更新不需要的行。

我认为您可以通过利用 SQL Server 可更新 CTE 的功能来解决此问题。这通过将您的SELECT查询转换为 CTE，然后UPDATE直接转换为 CTE 来实现（请注意，要使其正常工作，CTE 必须返回需要更新的列）。

WITH cte AS (
    SELECT c.ToMigrate, c.OpenTreatmentEpisodes
    FROM dbo.tblTreatment e
    INNER JOIN dbo.tblProgramAssessment pa ON pa.TreatmentID = e.TreatmentId
    INNER JOIN #Client c ON c.ClientId = e.ClientId
    LEFT JOIN dbo.tblCessationOfTreatment ct ON ct.TreatmentId = e.TreatmentId
    LEFT JOIN dbo.tblClientGP m ON m.ClientId = c.ClientId
    WHERE  
           e.IsOpen = 1 
           AND e.IsDeleted = 0 
           AND ct.CessationDate is null
           AND c.IsDeceased = 0 
)
UPDATE cte SET ToMigrate = 1, OpenTreatmentEpisodes = 1
于 2020-02-05T22:38:57.503 回答