Question

我有2张桌子，我需要使用CTE。

我需要Table_2行上Table_1的一组行，dActiveDate中table_1最大，table_1.dActiveDate <= table_2.dDateFactor table_1.dcidKala = table_2.dcidKala }}

   CREATE TABLE #Table_1
(
    dcidKala              INT,
    dcPercentDiscount     FLOAT,
    dActiveDate           DATE
)

CREATE TABLE #Table_2
(
    dcRow           INT,
    dcidKala        INT,
    dcNum           FLOAT,
    dDateFactor     DATE
)

INSERT INTO #Table_1
  (
    dcidKala,
    dcPercentDiscount,
    dActiveDate
  )
VALUES
(109,10,'2017-08-23' ),
(109, 15, '2017-10-12'),
(100, 20, '2017-01-20'),
(102, 20, '2017-01-20')

INSERT INTO #Table_2
  (
    dcRow,
    dcidKala,
    dcNum,
    dDateFactor
  )
VALUES
( 1,109,1,  '2017-10-05'  ),
(2, 109, 2, '2017-10-07'),
(3, 109, 1, '2017-10-14'),
(4, 109, 5, '2017-10-19'),
(5, 100, 2, '2017-01-25')

;WITH cte AS 
(
    SELECT th.dcPercentDiscount,
           tb.dcRow,
           ROW_NUMBER() OVER(PARTITION BY th.dcidKala, tb.dcRow ORDER BY th.dActiveDate) AS 
           rn
    FROM   #Table_1 th
           INNER JOIN #Table_2 tb
                ON  tb.dcidKala = th.dcidKala
                AND tb.dDateFactor >= th.dActiveDate
)

SELECT *
FROM   #Table_2 t2
       LEFT JOIN cte t3
            ON  t2.dcRow = t3.dcRow
            AND t3.rn = 1


DROP TABLE [#Table_1]
DROP TABLE [#Table_2]

--result myCode is:
  --1   109 1   2017-10-05  10  1   1
  --2   109 2   2017-10-07  10  2   1
  --3   109 1   2017-10-14  10  3   1
  --4   109 5   2017-10-19  10  4   1
  --5   100 2   2017-01-25  20  5   1

  --Rows 3 and Rows 4  is wrong

  --i need this result : 
  -- on Result From table_1 on table_2
  --1   109 1   2017-10-05  10  1   1
  --2   109 2   2017-10-07  10  2   1
  --3   109 1   2017-10-14  15  3   1
  --4   109 5   2017-10-19  15  4   1
  --5   100 2   2017-01-25  20  5   1

对于table_2中的每一行，只有一个来自table_1的最大结果 dActiveDate和较小的dDateFactor

请帮帮我

谢谢

Answer 1

CREATE TABLE #Table_1 (dcidKala          INT,
                       dcPercentDiscount FLOAT,
                       dActiveDate       DATE)

CREATE TABLE #Table_2 (dcRow       INT,
                       dcidKala    INT,
                       dcNum       FLOAT,
                       dDateFactor DATE)

INSERT INTO #Table_1 (dcidKala,
                      dcPercentDiscount,
                      dActiveDate)
VALUES (100, 10, '2017-01-01'),
(101, 15, '2017-01-02'),
(100, 20, '2017-01-20'),
(102, 20, '2017-01-20')

INSERT INTO #Table_2 (dcRow,
                      dcidKala,
                      dcNum,
                      dDateFactor)
VALUES (1, 100, 1, '2017-01-05'),
(2, 100, 2, '2017-01-09'),
(3, 101, 1, '2017-01-01'),
(4, 101, 5, '2017-01-20'),
(5, 100, 2, '2017-01-25')

SELECT  *
FROM    [#Table_2] AS [t2]
CROSS APPLY (   SELECT  TOP 1 *
                FROM    (   SELECT  TOP 1 [t1].[dcidKala],
                                    [t1].[dcPercentDiscount],
                                    [t1].[dActiveDate]
                            FROM    [#Table_1] AS [t1]
                            WHERE  [t1].[dcidKala] = [t2].[dcidKala]
                                   AND [t2].[dDateFactor] >= [t1].[dActiveDate]
                            ORDER BY [t1].[dActiveDate] DESC
                            UNION ALL
                            SELECT  NULL,
                                    NULL,
                                    NULL) t3
                ORDER BY CASE
                             WHEN [t2].[dcidKala] IS NOT NULL THEN 0
                             ELSE 1
                         END) AS t1

DROP TABLE [#Table_1]
DROP TABLE [#Table_2]

Answer 2

你可以使用它。

;WITH cte AS 
(
    SELECT 
        th.dcPercentDiscount, tb.dcRow, 
        ROW_NUMBER() OVER(PARTITION BY th.dcidKala, tb.dcRow ORDER BY th.dActiveDate DESC) AS rn
    FROM   
        Table_1 th
    INNER JOIN 
        Table_2 tb ON tb.dcidKala = th.dcidKala
                   AND tb.dDateFactor >= th.dActiveDate
)
SELECT * 
FROM Table_2 t2
LEFT JOIN cte t3 ON t2.dcRow = t3.dcRow and t3.rn=1

我需要使用CTE和两个表

2 个答案: