使用变量而不是 UNION 查询

Question

我正在尝试使用可变条件编写查询。有没有办法在不使用联合的情况下执行以下操作，而是使用另一个表中的日期列表？

SELECT
'2014-03-03' AS SnapshotDate
,T2.Pre_PPI_Cycle
,SUM(ISNULL(T2.Pre_PPI_Balance, 0))AS Pre_Balance
,COUNT(ISNULL(T2.Account_Number, 0)) AS Pre_Volume
,ROW_NUMBER() OVER (PARTITION BY Account_Number 
ORDER BY Account_Number, SnapshotDate DESC) AS ROW
FROM #TABLE_1 AS T2
WHERE T2.SnapshotDate <= '2014-03-03'
GROUP BY T2.SnapshotDate, T2.Pre_PPI_Cycle, Account_Number
UNION
SELECT
'2014-03-04' AS SnapshotDate
,T2.Pre_PPI_Cycle
,SUM(ISNULL(T2.Pre_PPI_Balance, 0))AS Pre_Balance
,COUNT(ISNULL(T2.Account_Number, 0)) AS Pre_Volume
,ROW_NUMBER() OVER (PARTITION BY Account_Number 
ORDER BY Account_Number, SnapshotDate DESC) AS ROW
FROM #PPI_3 AS T2
WHERE T2.SnapshotDate <= '2014-03-04'
GROUP BY T2.SnapshotDate, T2.Pre_PPI_Cycle, Account_Number

编辑

感谢到目前为止的帮助 - 只是为了澄清 - 这是我现在拥有的代码。

SELECT
 T2.Capture_Date
,T1.Pre_PPI_Cycle
,SUM(ISNULL(T1.Pre_PPI_Balance, 0))AS Pre_Balance
,COUNT(ISNULL(T1.Account_Number, 0)) AS Pre_Volume
,ROW_NUMBER() OVER (PARTITION BY T1.Account_Number 
 ORDER BY T1.Account_Number, T1.SnapshotDate DESC) AS ROW
FROM 
#PPI_3 AS T1
INNER JOIN (SELECT CHILD.Capture_Date
FROM #DATES AS CHILD
WHERE CHILD.Capture_Date <= '2014-03-04') T2
ON T2.Capture_Date = T1.SnapshotDate
GROUP BY T2.Capture_Date, T1.SnapshotDate, T1.Pre_PPI_Cycle, T1.Account_Number

我在下面的 cmets 中提到，我希望将日期“2014-03-04”更改为保存在 #DATES 表中的日期列表。例如，如果日期

感谢到目前为止大家的帮助 - 感觉我们正在取得进展！

谢谢，山姆

Answer 1

DECLARE @mydate smalldatetime

set @mydate = '2014-03-03';

SELECT
    '2014-03-03' AS SnapshotDate
    ,T2.Pre_PPI_Cycle
    ,SUM(ISNULL(T2.Pre_PPI_Balance, 0))AS Pre_Balance
    ,COUNT(ISNULL(T2.Account_Number, 0)) AS Pre_Volume
    ,ROW_NUMBER() OVER (PARTITION BY Account_Number ORDER BY Account_Number, SnapshotDate      DESC) AS ROW
FROM #TABLE_1 AS T2
INNER JOIN ( SELECT T2.ID, myDate
             FROM #TABLE_1 AS T2
            WHERE T2.SnapshotDate <= @mydate
           ) x
           ON x.myDate = T2.SnapshotDate
           AND x.ID = T2.ID
GROUP BY T2.SnapshotDate, T2.Pre_PPI_Cycle, Account_Number

或

SELECT
     '2014-03-03' AS SnapshotDate
    ,T2.Pre_PPI_Cycle
    ,SUM(ISNULL(T2.Pre_PPI_Balance, 0))AS Pre_Balance
    ,COUNT(ISNULL(T2.Account_Number, 0)) AS Pre_Volume
    ,ROW_NUMBER() OVER (PARTITION BY Account_Number ORDER BY Account_Number, SnapshotDate DESC) AS ROW
FROM #TABLE_1 AS T2
WHERE T2.SnapshotDate IN ( SELECT myDate
          FROM #TABLE_1 AS T2
          WHERE T2.SnapshotDate <= '2014-03-03' )
GROUP BY T2.SnapshotDate, T2.Pre_PPI_Cycle, Account_Number

---

根据您的最新更新。我会做以下事情，因为它更容易一点：

SELECT
 T1.Capture_Date
,T1.Pre_PPI_Cycle
,SUM(ISNULL(T1.Pre_PPI_Balance, 0))AS Pre_Balance
,COUNT(ISNULL(T1.Account_Number, 0)) AS Pre_Volume
,ROW_NUMBER() OVER (PARTITION BY T1.Account_Number 
 ORDER BY T1.Account_Number, T1.SnapshotDate DESC) AS ROW
FROM #PPI_3 AS T1
WHERE T1.Capture_Date IN ( 
    SELECT CHILD.Capture_Date 
    FROM #DATES AS CHILD 
    WHERE CHILD.Capture_Date <= '2014-03-04')
GROUP BY T1.Capture_Date, T1.SnapshotDate, T1.Pre_PPI_Cycle, T1.Account_Number