sql - JOINING 来自两个 SELECT 状态的结果，每个状态都有自己的 WHERE 标准和 GROUPING

Question

我有以下两个 Select 语句-

SELECT * 
FROM tblAllocations
WHERE AllocID IN
(
    SELECT MAX(AllocID)    
    FROM tblAllocations
    WHERE FeeEarner = 'KLW' AND [Date] <= '2013-12-31'
    GROUP BY FeeEarner, CaseNo

和

SELECT UserID, CaseNo, SUM(Fees) AS [Fees]
FROM tblTimesheetEntries
WHERE UserID = 'KLW' AND [Date] <= '2013-12-31'
GROUP BY UserID, CaseNo

返回以下结果 -

我想要的是将它们组合在一个 Select 语句中，该语句从第一个查询中提取一些字段，从第二个查询中提取其他字段。根据上面的结果，应该只返回 5 行，其中 3 行将包含来自两个 Query 的字段，2 个将只有来自一个 Query 的字段（因此它会有一些 NULL 值）

我尝试了以下 -

SELECT q1.CaseNo, q1.FeeEarner, 
       q2.Fees AS [Fees], 
       q1.Fees AS [Billed], 
      (q2.Fees - q1.Fees) AS WIP
FROM
(
    SELECT * 
    FROM tblAllocations
    WHERE AllocID IN
    (
        SELECT MAX(AllocID)    
        FROM tblAllocations
        WHERE FeeEarner = 'KLW'
        AND [Date] <= '2013-12-31'
        GROUP BY FeeEarner, CaseNo
    )
) AS q1,
(
    SELECT UserID, CaseNo, SUM(Fees) AS [Fees]
    FROM tblTimesheetEntries
    WHERE UserID = 'KLW'
    AND [Date] <= '2013-12-31'
    GROUP BY UserID, CaseNo
) AS q2

然而，这就像一个交叉连接，并给了我 15 行如下 -

有人可以建议我如何正确组合这两个查询以便只返回 5 行。

Answer 1

以下是更正后的查询：

 SELECT q1.CaseNo, q1.FeeEarner, 
           q2.Fees AS [Fees], 
           q1.Fees AS [Billed], 
          (q2.Fees - q1.Fees) AS WIP
    FROM
    (
    SELECT * 
    FROM tblAllocations
    WHERE AllocID IN
    (
    SELECT MAX(AllocID)    
    FROM tblAllocations
    WHERE FeeEarner = 'KLW'
    AND [Date] <= '2013-12-31'
    GROUP BY FeeEarner, CaseNo
    )
    ) AS q1,
    (
    SELECT UserID, CaseNo, SUM(Fees) AS [Fees]
    FROM tblTimesheetEntries
    WHERE UserID = 'KLW'
    AND [Date] <= '2013-12-31'
    GROUP BY UserID, CaseNo
    ) AS q2
    where q1.CaseNo = q2.CaseNo

Answer 2

它正在进行交叉连接，因为您没有说如何q1以及q2“相关”（已连接）。

此外，由于您需要五行（即，tblTimesheetEntries无论 in 匹配的所有行tblAllocations），您应该使用右连接（或左但反转q1and q2）：

SELECT
  q2.CaseNo,
  q1.FeeEarner,
  q2.Fees AS [Fees],
  q1.Fees AS [Billed],
  (q2.Fees - q1.Fees) AS WIP
FROM (
  SELECT * FROM tblAllocations
  WHERE AllocID IN (
    SELECT MAX(AllocID)
    FROM tblAllocations
    WHERE FeeEarner = 'KLW' AND [Date] <= '2013-12-31'
    GROUP BY FeeEarner, CaseNo
  )) AS q1
RIGHT JOIN (
  SELECT UserID, CaseNo, SUM(Fees) AS[Fees]
  FROM tblTimesheetEntries
  WHERE UserID = 'KLW'
  AND [Date] <= '2013-12-31'
  GROUP BY UserID, CaseNo
) AS q2
  ON q1.CaseNo = q2.CaseNo

SqlFiddle在这里。

Answer 3

我将从您的第二个查询开始，然后向您的第一个查询 LEFT-JOIN。第二个查询具有相应的案例编号 15、25 和 33，它们将显示所有列，还有案例 5 和 12，这将导致其他列的 NULL。

select 
      AllThese.UserID,
      AllThese.Fees,
      MaxAlloc.*
   from
      ( SELECT 
              UserID,
              CaseNo, 
              SUM(Fees) AS [Fees]
           FROM 
              tblTimesheetEntries
           WHERE 
                  UserID = 'KLW'
              AND [Date] <= '2013-12-31'
           GROUP BY 
              UserID, 
              CaseNo ) AllThese
      LEFT JOIN
      ( SELECT * 
           FROM tblAllocations
           WHERE AllocID IN
             ( SELECT MAX(AllocID)
                  FROM tblAllocations
                  WHERE FeeEarner = 'KLW'
                    AND [Date] <= '2013-12-31'
                  GROUP BY FeeEarner, CaseNo )) MaxAlloc
         on AllThese.CaseNo = MaxAlloc.CaseNo