Return 每个 ID 一个角色

Question

我想 return 每个员工 (EmpID) 只有一个角色，即最后一个执行特定任务 (FixEndDate) 的员工。以下是模型表。

DECLARE @Problem TABLE
(
        ProblemID   INT 
   , ProblemDate DATETIME
   , LogBy       NVARCHAR(50)  
)


INSERT INTO @Problem(ProblemID,ProblemDate,LogBy)
VALUES (1,CAST('2015-01-29 10:53:46.000'AS DATETIME),'Carl')
     , (2,CAST('2015-01-21 10:53:46.000'AS DATETIME),'Paul')
  , (3,CAST('2015-01-21 13:53:46.000'AS DATETIME),'Paul')
  , (4,CAST('2015-01-21 15:53:46.000'AS DATETIME),'Paul')

DECLARE @Fix TABLE 
(
        FixID        INT 
   , ProblemID    INT
   , EmpID        INT
   , FixStartDate DATETIME
   , FixEndDate   DATETIME
)


INSERT INTO @Fix(ProblemID, EmpID, FixStartDate, FixEndDate)
VALUES (1, 12, CAST('2015-02-02 10:53:46.000'AS DATETIME),CAST('2015-02-02 12:50:46.000'AS DATETIME))
     , (1, 14, CAST('2015-02-03 10:53:46.000'AS DATETIME),CAST('2015-02-03 12:50:46.000'AS DATETIME))
  , (2, 11, CAST('2015-02-04 10:53:46.000'AS DATETIME),CAST('2015-02-04 01:55:46.000'AS DATETIME))
  , (2, 12, CAST('2015-02-04 05:56:46.000'AS DATETIME),CAST('2015-02-03 08:50:46.000'AS DATETIME))
  , (3, 10, CAST('2015-02-04 07:53:46.000'AS DATETIME),CAST('2015-02-04 18:10:46.000'AS DATETIME))
  , (3, 15, CAST('2015-02-05 10:53:46.000'AS DATETIME),CAST('2015-02-05 12:10:46.000'AS DATETIME))
  , (3, 18, CAST('2015-02-05 11:53:46.000'AS DATETIME),CAST('2015-02-05 01:10:46.000'AS DATETIME))
  , (4, 20, CAST('2015-02-07 12:53:46.000'AS DATETIME),CAST('2015-02-08 03:10:46.000'AS DATETIME))
  , (4, 23, CAST('2015-02-08 11:53:46.000'AS DATETIME),CAST('2015-02-09 18:10:46.000'AS DATETIME))
  , (4, 13, CAST('2015-02-10 16:53:46.000'AS DATETIME),CAST('2015-02-11 16:10:46.000'AS DATETIME))

我试过：

    SELECT f.EmpID
         , p.ProblemID
         , p.ProblemDate
         , f.FixStartDate
         , f.FixEndDate
    FROM @Problem AS p 
    INNER JOIN @Fix AS f 
     ON p.ProblemID = f.ProblemID
    INNER JOIN (
        SELECT f.EmpID
             , p.ProblemID
             , p.ProblemDate
            , f.FixStartDate
            , MAX(f.FixEndDate) AS Fixed
        FROM @Problem AS p 
        INNER JOIN @Fix AS f 
        ON p.ProblemID = f.ProblemID
        GROUP BY f.EmpID
               , p.ProblemID
               , p.ProblemDate
               , f.FixStartDate
        ) AS d
          ON d.EmpID = f.EmpID
          AND d.Fixed = f.FixEndDate
 ORDER BY FixEndDate DESC

前进的方向是什么？

Answer 1

尝试

 SELECT f.EmpID
         , p.ProblemID
         , p.ProblemDate
         , f.FixStartDate
         , f.FixEndDate
    FROM @Problem AS p 
    INNER JOIN (select * from (select * ,row_number() over (partition by ProblemID order by fixenddate desc) as rno from @Fix) t where rno=1) AS f 
     ON p.ProblemID = f.ProblemID

Return 每个 ID 一个角色

Return one role per ID

tsql

ssms

sql-server-2008