左外Select查詢連接返回從主表

Question

好太多結果，這裏的select語句

SELECT dbo.tbl_inspectors.user_firstname, 
     dbo.tbl_inspectors.user_lastname, 
     dbo.tbl_inspectors.user_loc, 
     dbo.tbl_appraisals.appPartA, 
     dbo.tbl_appraisals.appPartB, 
     dbo.tbl_appraisals.appAppraised, 
     dbo.tbl_appraisals.appFinalized, 
     dbo.tbl_appraisals.appDate, 
     dbo.tbl_inspectors.appProcStart, 
     dbo.tbl_inspectors.appDue, 
     dbo.tbl_inspectors.inspAdhocStaff, 
     dbo.tbl_inspectors.access_id, 
     dbo.tbl_appraisals.appraiseID, dbo.tbl_inspectors.user_id 
FROM dbo.tbl_inspectors 
     LEFT OUTER JOIN 
     dbo.tbl_appraisals ON dbo.tbl_inspectors.user_id = bo.tbl_appraisals.inspectID 

如果有反對的tbl_appraisals表tbl_inspectors.user_id多個結果，然後我得到了多個結果每個檢查員，我只是想要它從tbl_appraisals對tbl_inspectors user_id拉最近的比賽，我怎麼能做到這一點？

PS tbl_appraisals.appDate是確定從tbl_appraisals

Answer 1

假設引擎的最近結果字段不MySQL的

這是一個「每組TOP 1」的問題

SELECT 
    * 
FROM 
    (
    SELECT I.user_firstname, 
      I.user_lastname, 
      I.user_loc, 
      A.appPartA, 
      A.appPartB, 
      A.appAppraised, 
      A.appFinalized, 
      A.appDate, 
      I.appProcStart, 
      I.appDue, 
      I.inspAdhocStaff, 
      I.access_id, 
      A.appraiseID, 
      I.USER_ID, 
      ROW_NUMBER() OVER (PARTITION BY I.user_id ORDER BY COALESCE(A.appDate, '19000101') DESC) AS rn 
    FROM dbo.tbl_inspectors I 
      LEFT OUTER JOIN 
      dbo.tbl_appraisals A ON I.user_id = A.inspectID 
    ) X 
WHERE 
    X.rn = 1