SQL 重复行多个连接

Question

在 SQL 方面，我几乎是个菜鸟，因此我们将不胜感激。我有一个大型数据集，我正在为一家医院过滤。我从 6 个不同的 tables 中提取数据，而我的一个 tables 每次访问都有重复的行。我只想为每次访问拉入一行（拉入哪一行并不重要）。我知道我需要使用 DISTINCT 或 GROUP BY 子句，但我的语法一定是错误的。

    SELECT
         ADV.[VisitID]          AS  VisitID
        ,ADV.[Name]             AS  Name
        ,ADV.[UnitNumber]       AS  UnitNumber
        ,CONVERT(DATE,ADV.[BirthDateTime])                          AS  BirthDate
        ,ADV.[ReasonForVisit]   AS  ReasonForVisit
        ,ADV.[AccountNumber]    AS  AccountNumber
        ,DATEDIFF(day, ADV.ServiceDateTime, DIS.DischargeDateTime)  AS LOS
        ,ADV.[HomePhone]        AS  PhoneNumber
        ,ADV.[ServiceDateTime]  AS  ServiceDateTime
        ,ADV.[Status]           AS  'Status'
        ,PRV.[PrimaryCareID]    AS  PCP
        ,LAB.[TestMnemonic]     AS  Test
        ,LAB.[ResultRW]         AS  Result
        ,LAB.[AbnormalFlag]     AS  AbnormalFlag
        ,LAB.[ResultDateTime]   AS  ResultDateTime
        ,DIS.[Diagnosis]        AS  DischargeDiagnosis
        ,DIS.[ErDiagnosis]      AS  ERDiagnosis
        ,DCP.[TextLine]         AS  ProblemList


FROM          Visits                                      ADV
    LEFT JOIN Tests                                       LAB             ON ( LAB.VisitID  = ADV.VisitID AND
                                                                               LAB.SourceID = ADV.SourceID )
    LEFT JOIN Discharge                                   DIS             ON ( DIS.VisitID  = LAB.VisitID AND
                                                                               DIS.SourceID = LAB.SourceID )
    LEFT JOIN Providers                                   PRV             ON ( PRV.VisitID  = DIS.VisitID AND
                                                                               PRV.SourceID = DIS.SourceID )
    LEFT JOIN ProblemListVisits                           EPS             ON ( EPS.VisitID  = PRV.VisitID AND
                                                                               EPS.SourceID = PRV.SourceID )                                                                                                 
    LEFT JOIN ProblemList                                 DCP             ON ( DCP.PatientID = EPS.PatientID AND
                                                                               DCP.SourceID  = EPS.SourceID )


WHERE ( DCP.[TextLine]       LIKE '%Diabetes%'          OR 
        DCP.[TextLine]       LIKE '%Diabetic%'          OR
        DCP.[TextLine]       LIKE '%DM2%'               OR
        DCP.[TextLine]       LIKE '%DKA%'               OR
        DCP.[TextLine]       LIKE '%Hyperglycemia%'     OR
        DCP.[TextLine]       LIKE '%Hypoglycemia%'    ) AND
      ( LAB.[TestMnemonic] = 'GLU'                      OR
        LAB.[TestMnemonic] = '%HA1C'                  ) AND
        ADV.[Status]      != 'DIS CLI'                )

所以这没问题，但是当医生进入患者的问题列表并进行更改时，它会重新归档整个列表，从而再次填充问题列表 table。因此，对于 1 次访问，由于问题列表，我可能会得到 4 个重复条目，而我只想要一个。哪个也无所谓。

我尝试引用其他问题并在其中嵌套另一个 SELECT 语句，但我总是遇到语法错误。

这是重复值的样子：

1111111111  SMITH,JOHN  1111    1/1/1901    CHEST PAIN  1111    2   111-111-1111    1/1/1901 12:15  DIS IN  DOEJO   GLU 120  H  1/2/1901 6:35   NULL    CHEST PAIN  Diabetes type 2, controlled
1111111111  SMITH,JOHN  1111    1/1/1901    CHEST PAIN  1111    2   111-111-1111    1/1/1901 12:15  DIS IN  DOEJO   GLU 120  H  1/2/1901 6:35   NULL    CHEST PAIN  Diabetes type 2, controlled
1111111111  SMITH,JOHN  1111    1/1/1901    CHEST PAIN  1111    2   111-111-1111    1/1/1901 12:15  DIS IN  DOEJO   GLU 120  H  1/2/1901 6:35   NULL    CHEST PAIN  Diabetes type 2, controlled
1111111111  SMITH,JOHN  1111    1/1/1901    CHEST PAIN  1111    2   111-111-1111    1/1/1901 12:15  DIS IN  DOEJO   GLU 120  H  1/2/1901 6:35   NULL    CHEST PAIN  Diabetes type 2, controlled

最后，'Diabetes type 2, controlled' 是导致重复的原因。如果我从查询中删除 ProblemListVisit 和 ProblemList tables，我只会得到一行数据。

最重要的是获得所有独特的测试结果，但不是问题列表中所有重复的条目（只想知道他们患有哪种类型的糖尿病，一次）。

谢谢！

Answer 1

Distinct 子句应该可以解决问题但如果没有，您可以更改

LEFT JOIN ProblemList   DCP             ON ( DCP.PatientID = EPS.PatientID AND
                                             DCP.SourceID  = EPS.SourceID )

为

OUTER APPLY (Select top 1 DCP.[TextLine]  FROM  ProblemList   DCP WHERE
                                             DCP.PatientID = EPS.PatientID  
                                           AND DCP.SourceID  = EPS.SourceID) DCP

Answer 2

尝试在 SELECT 之后添加 DISTINCT。像这样：

SELECT DISTINCT
     ADV.[VisitID]          AS  VisitID
    ,ADV.[Name]             AS  Name 
    ...

Answer 3

代替 DISTINCT ，我认为这是实现此目标的最快方法，您还可以将生成多行的每个 table 移动到子查询中，在其中 GROUP BY您为 JOINS 和 SELECTS 寻找的值。

这里有两个优点：

您可以更好地控制这些更精细的 table 和
您减少了 JOIN 的开销，这将减少您的 I/O 和 CPU 使用，当您使用子查询中的 WHERE 子句限制它们允许通过的内容时。

代码：

SELECT
         ADV.[VisitID]          AS  VisitID
        ,ADV.[Name]             AS  Name
        ,ADV.[UnitNumber]       AS  UnitNumber
        ,CONVERT(DATE,ADV.[BirthDateTime])                          AS  BirthDate
        ,ADV.[ReasonForVisit]   AS  ReasonForVisit
        ,ADV.[AccountNumber]    AS  AccountNumber
        ,DATEDIFF(day, ADV.ServiceDateTime, DIS.DischargeDateTime)  AS LOS
        ,ADV.[HomePhone]        AS  PhoneNumber
        ,ADV.[ServiceDateTime]  AS  ServiceDateTime
        ,ADV.[Status]           AS  'Status'
        ,PRV.[PrimaryCareID]    AS  PCP
        ,LAB.[TestMnemonic]     AS  Test
        ,LAB.[ResultRW]         AS  Result
        ,LAB.[AbnormalFlag]     AS  AbnormalFlag
        ,LAB.[ResultDateTime]   AS  ResultDateTime
        ,DIS.[Diagnosis]        AS  DischargeDiagnosis
        ,DIS.[ErDiagnosis]      AS  ERDiagnosis
        ,DCP.[TextLine]         AS  ProblemList


FROM          Visits                                      ADV
    LEFT JOIN Tests                                       LAB             ON ( LAB.VisitID  = ADV.VisitID AND
                                                                               LAB.SourceID = ADV.SourceID )
    LEFT JOIN Discharge                                   DIS             ON ( DIS.VisitID  = LAB.VisitID AND
                                                                               DIS.SourceID = LAB.SourceID )
    LEFT JOIN Providers                                   PRV             ON ( PRV.VisitID  = DIS.VisitID AND
                                                                               PRV.SourceID = DIS.SourceID )
    LEFT JOIN 
        (
            SELECT 
                VisitID, 
                SourceID, 
                PatientID
            FROM ProblemListVisits 
            GROUP BY 
                VisitID, 
                SourceID, 
                PatientID
        )                                                 EPS             ON ( EPS.VisitID  = PRV.VisitID AND
                                                                               EPS.SourceID = PRV.SourceID )                                                                                                 
    LEFT JOIN 
        (
            SELECT 
                PatientID, 
                SourceID, 
                TextLine 
            FROM ProblemList 
            WHERE 
                [TextLine]       LIKE '%Diabetes%'          OR 
                [TextLine]       LIKE '%Diabetic%'          OR
                [TextLine]       LIKE '%DM2%'               OR
                [TextLine]       LIKE '%DKA%'               OR
                [TextLine]       LIKE '%Hyperglycemia%'     OR
                [TextLine]       LIKE '%Hypoglycemia%' 
            GROUP BY 
                PatientID, 
                SourceID, 
                TextLine 
        )                                                  DCP             ON ( DCP.PatientID = EPS.PatientID AND
                                                                               DCP.SourceID  = EPS.SourceID )


WHERE ( LAB.[TestMnemonic] = 'GLU'                      OR
        LAB.[TestMnemonic] = '%HA1C'                  ) AND
        ADV.[Status]      != 'DIS CLI'                )

如果您仍然得到倍数，则表明 [TextLine] 对您的问题列表 table 中的每个 VisitID/PatientID 组合都有一个以上的值。届时，您可以从 GROUP BY 子句中删除该字段，并在该字段上使用某种聚合，例如子查询中的 MAX([TextLine]) 。不过，我怀疑在使用 DISTINCT 或使用此子查询方法后不会有重复项。

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