mysql - 未使用带有 ID 的Where子句时没有结果集

Question

我试图找出为什么当我取出 Account_ID 时我的代码没有返回任何数据。我希望它运行并找到满足连接条件的每个 Account_ID 以及我想要返回的字段。这是在 MySQL 中，我环顾四周并用 Google 搜索，但没有找到类似的东西，或者只是没有正确地放置它。因此，下面是代码，如果有人可以帮助我，我将不胜感激。该代码应为每个 Account_ID 返回 1 行我不习惯使用MySQL。版本 5.6.34 使用 Toad Data-Point 运行 sql 脚本。谢谢丹

    SELECT DISTINCT
    pd.ACCOUNT_ID                 
    , do.MEMBER_NAME
    , do.GENDER
    , MaxDate.EarlyDATE AS ACTIVITY_DATE
    , MaxDate.LateDATE  AS LAST_ACTIVITY_DATE
    , pd.NUMBER_WKS        
    ... more fields after this
    Joins below
    FROM ZZ_Program_Details pd 
        LEFT JOIN ZZ_Demographics do 
         ON do.ACCOUNT_ID = pd.ACCOUNT_ID
    INNER JOIN 
        (SELECT DISTINCT cl.ACCOUNT_ID
        , min(cl.activity_date)  AS EarlyDATE
        , cl1.activity_date AS LateDATE
        , cl1.scheduling_selection
        , cl.ATND_STATUS_THIS_INTERVAL         
        , cl.WEIGHT_STATUS_FOR_INTERVAL        
        , TRUNCATE(cl.WEIGHT_WHEN_ENROLLED,2)   AS WEIGHT_WHEN_ENROLLED
        , TRUNCATE(cl.WEIGHT_AT_INTERVAL_END,2) AS WEIGHT_AT_INTERVAL_END
        FROM ZZ_Class_Attendance cl
         INNER JOIN ZZ_Class_Attendance cl1
          ON cl1.account_id = cl.ACCOUNT_ID 
        WHERE cl1.ACTIVITY_DATE > cl.ACTIVITY_DATE
         /*and cl.account_id = '47F74C65BA8BB02DE053BC010B0AF714'*/
        ) AS MaxDate 
    INNER JOIN 
     (SELECT ESRA.healthfleet_member_id
      , ESRA.Sponsor
      , ESRA.uhc_region
      , ESRA.uhc_major_market
      , ESRA.uhc_minor_market AS ESRA_UHC_MINOR_MARKET
      , ESRA.policy_number AS ESRA_POLICY_NBR
      , ESRA.relationship_code
      , sf.Market_Segment
      , sf.UHC_Minor_Market   AS SF_UHC_MINOR_MARKET
      , sf.CLIENT_NAME
      , sf.Client_Owner
      , sf.Payer_Effective_Date
    FROM reporting_adhoc.ZZ_ESRA_People ESRA
     LEFT JOIN reporting_adhoc.ZZ_Salesforce sf
      ON sf.Policy_Number = ESRA.policy_number
    /*WHERE ESRA.healthfleet_member_id='47F74C65BA8BB02DE053BC010B0AF714'*/
    GROUP BY ESRA.healthfleet_member_id
    , ESRA.Sponsor, ESRA.uhc_region
    , ESRA.uhc_major_market
    , ESRA.uhc_minor_market
    , ESRA.relationship_code
    , sf.Market_Segment
    , sf.UHC_Minor_Market
    , sf.CLIENT_NAME
    , sf.Client_Owner, ESRA.policy_number
    , sf.Payer_Effective_Date
    ) ESRA_DATA 

    ON MaxDate.ACCOUNT_ID = pd.ACCOUNT_ID
    AND ESRA_DATA.healthfleet_member_id = pd.ACCOUNT_ID

    /*WHERE pd.account_id = '47F74C65BA8BB02DE053BC010B0AF714'* --with this 
    it works fine */ 
    WHERE pd.account_id > 0 --an attempt with getting all account_ids

    GROUP BY
    pd.ACCOUNT_ID                 
    , do.MEMBER_NAME  
    , do.GENDER
    , MaxDate.EarlyDATE
    , MaxDate.LateDATE
    ... rest of fields
    ORDER BY pd.ACCOUNT_ID

Answer 1

如果无法访问您的表格和数据，我们可能无法提出明确的答案，并且由于您的查询缺少部分，这使其更像是一个猜谜游戏。

让我们从这里开始:

SELECT DISTINCT  ---------- bad bad
      pd.ACCOUNT_ID
    , MaxDate.EarlyDATE AS ACTIVITY_DATE
    , MaxDate.LateDATE  AS LAST_ACTIVITY_DATE

FROM ZZ_Program_Details pd
LEFT JOIN ZZ_Demographics do ON do.ACCOUNT_ID = pd.ACCOUNT_ID
INNER JOIN (
      SELECT DISTINCT  ---------- bad bad
            cl.ACCOUNT_ID
          , MIN(cl.activity_date) AS EarlyDATE
          , cl1.activity_date     AS LateDATE
      FROM ZZ_Class_Attendance cl
      INNER JOIN ZZ_Class_Attendance cl1 ON cl1.account_id = cl.ACCOUNT_ID
      WHERE cl1.ACTIVITY_DATE > cl.ACTIVITY_DATE

      -- no GROUP BY, so how do your get MIN() or MAX() ?

   ) AS MaxDate ON 
                    ( WHAT???? )

首先将大查询分解为更小的 block ，如上所示。 此部分查询有效吗？ 可能不会，因为您尝试使用 DISTINCT 而不是 GROUP BY 并且连接条件也未知。

另请注意，您使用了 INNER JOIN。如果该子查询 MaxDate 无法返回任何匹配的行，则整个查询也将不会返回行。重新考虑每个 INNER JOIN(也许尝试将它们作为 LEFT JOINS)。

一旦部分查询开始工作，请添加下一个联接并将相关列添加到顶部 select 子句。处理查询的这一部分，直到成功，然后移至下一部分并重复，直到获得有效的查询。

请尽量避免在涉及多个连接的复杂查询中使用“select unique”。这不是一个好的做法。

<小时/>

您可能会发现这些查询将帮助您确定哪些表(或子查询)需要左连接:

SELECT COUNT(distinct pd.ACCOUNT_ID) acct_c, COUNT(*) row_c
FROM ZZ_Program_Details pd 
;

SELECT COUNT(distinct pd.ACCOUNT_ID) acct_c, COUNT(*) row_c
FROM ZZ_Program_Details pd 
INNER JOIN ZZ_Demographics do ON pd.ACCOUNT_ID = do.ACCOUNT_ID
;

SELECT COUNT(distinct pd.ACCOUNT_ID) acct_c, COUNT(*) row_c
FROM ZZ_Program_Details pd 
LEFT JOIN ZZ_Demographics do ON pd.ACCOUNT_ID = do.ACCOUNT_ID
;

SELECT COUNT(distinct pd.ACCOUNT_ID) acct_c, COUNT(*) row_c
FROM ZZ_Program_Details pd 
INNER JOIN ZZ_Class_Attendance cl ON pd.ACCOUNT_ID = cl.ACCOUNT_ID
INNER JOIN ZZ_Class_Attendance cl1 ON cl1.account_id = cl.ACCOUNT_ID 
;

SELECT COUNT(distinct pd.ACCOUNT_ID) acct_c, COUNT(*) row_c
FROM ZZ_Program_Details pd 
LEFT JOIN ZZ_Class_Attendance cl ON pd.ACCOUNT_ID = cl.ACCOUNT_ID
LEFT JOIN ZZ_Class_Attendance cl1 ON cl1.account_id = cl.ACCOUNT_ID 
;

SELECT COUNT(distinct pd.ACCOUNT_ID) acct_c, COUNT(*) row_c
FROM ZZ_Program_Details pd 
INNER JOIN reporting_adhoc.ZZ_ESRA_People ESRA ON pd.ACCOUNT_ID = ESRA.healthfleet_member_id
INNER JOIN reporting_adhoc.ZZ_Salesforce sf ON sf.Policy_Number = ESRA.policy_number
;

SELECT COUNT(distinct pd.ACCOUNT_ID) acct_c, COUNT(*) row_c
FROM ZZ_Program_Details pd 
LEFT JOIN reporting_adhoc.ZZ_ESRA_People ESRA ON pd.ACCOUNT_ID = ESRA.healthfleet_member_id
LEFT JOIN reporting_adhoc.ZZ_Salesforce sf ON sf.Policy_Number = ESRA.policy_number
;