SQL中的嵌套CASE [英] Nested CASE in SQL

问题描述

TABLE1:

ARTIKEL      SUPPLIERID   SALE_SUM_PIECES   
TV            SONY            7            

TABLE2:

 ROW_ID     ARTIKEL      SUPPLIERID     PIECES    
    1           TV            SONY       6       
    2           TV            SONY       10      
    3           TV            SONY       6      
    4           TV            SONY       14       
    5           TV            SONY       18      
    6           TV            SONY       4  

仅当值TABLE1."SALE_SUM_PIECES"小于TABLE2中的"PIECES"的总和时，我才需要在TABLE2."PIECES"上减去值X=23.例如:TABLE1."SALE_SUM_PIECES"的值是7.现在，我需要检查TABLE2."PIECES"的总和7 goes less than在哪一行.在下面的示例中，TABLE2中的第一行无效，因为7大于6.但是TABLE2中的第二行有效，因为SUM表2中第1行和第2行的部分"的OF大于6，即6 + 10 = 16.因此，我需要从第二行减去TABLE2中的后续行减去X=23的值. 我的查询如下:

I need to subtract value X=23 on TABLE2."PIECES", only when the value TABLE1."SALE_SUM_PIECES" is less than the SUM of "PIECES" in TABLE2. For example: the value of TABLE1."SALE_SUM_PIECES" is 7. NOw I need to check at which row the value 7 goes less than the SUM of TABLE2."PIECES".In the below example the first row in TABLE2 is not valid because 7 is greater than 6. But the second row in TABLE2 is valid since the SUM OF "PIECES" from row1 and row2 in TABLE2 i.e 6+10=16 is greater than 7. So, I need to subtract value of X=23 from the second row to the following rows in TABLE2. The query I have is as follows:

SELECT "SUPPLIERID", "ARTIKEL",
    (case when ( cumulativesum - (select "SALE_SUM_PIECES" from  T1 where T1."SUPPLIERID"=T2."SUPPLIERID" and T1."ARTIKEL" = T2."ARTIKEL" )) <= 0
        then NULL
        when ( cumulativesum - (select "SALE_SUM_PIECES" from  TABLE1 T1 where T1."SUPPLIERID"=T2."SUPPLIERID" and T1."ARTIKEL" = T2."ARTIKEL" )) > 0 
        then
            (case when @x - cumulativesum <= 0 and @x - (cumulativesum -PIECES) > 0
                 then 0
                 when @x - "cumulativesum" <= 0
                 then NULL
                 else @x - "cumulativesum"
            end) as "VALUE_DRILL_DOWN"
    from (SELECT T1."ARTIKEL", T1."SUPPLIERID", T1.PIECES
             (select sum("PIECES")
              from EXAMPLE_TABLE T2
              where T2."ROW_ID" <= T1."ROW_ID" and T2."SUPPLIERID" = T1."SUPPLIERID" and T2."ARTIKEL"=T1."ARTIKEL"
             ) as "cumulativesum"
     from EXAMPLE_TABLE T1
     ) 

当我执行上面的查询时，我得到的结果如下:

When I execute the above query I get the result as follows:

 ROW_ID     ARTIKEL      SUPPLIERID    PIECES     VALUE_DRILL_DOWN
    1           TV            SONY      6            NULL
    2           TV            SONY      10           7
    3           TV            SONY      6            1
    4           TV            SONY      14           0
    5           TV            SONY      18           Null
    6           TV            SONY       4           Null 

但是我希望结果如下:

   ROW_ID       ARTIKEL      SUPPLIERID    PIECES    VALUE_DRILL_DOWN
    1           TV            SONY           6           NULL
    2           TV            SONY          10           13
    3           TV            SONY          6            7
    4           TV            SONY          14           0
    5           TV            SONY          18           Null
    6           TV            SONY          4            Null

我希望"X = 23"的减法从表2中条件TABLE1."SALE_SUM_PIECES" < TABLE2."PIECES"的行开始，即从行2开始.有什么建议?

I want the subtraction of ´X=23´ to start from the row in TABLE2 where the condition TABLE1."SALE_SUM_PIECES" < TABLE2."PIECES" i.e from row2. Any suggestions?

谢谢.

推荐答案

以下解决方案可提供所需的结果.参见 SqlFiddle

The below solution gives the desired results. See SqlFiddle

1   TV  SONY    922 6   110 2.50    NULL
2   TV  SONY    922 10  80  1.00    13
3   TV  SONY    922 6   65  1.50    7
4   TV  SONY    922 14  95  1.50    0
5   TV  SONY    922 18  95  1.50    NULL
6   TV  SONY    922 4   95  1.50    NULL



DECLARE @x INT = 23

; WITH cte AS
(
    SELECT t2.*, t1.SALE_SUM_PIECES,
            CASE 
                WHEN SUM(t2.PIECES) OVER (PARTITION BY t2.ARTIKEL, t2.SUPPLIERID ORDER BY ROW_ID) < t1.SALE_SUM_PIECES THEN 'None'
                ELSE t2.ARTIKEL + t2.SUPPLIERID
            END AS GroupId
    FROM @Table2 t2
    JOIN @Table1 t1 ON t2.ARTIKEL = t1.ARTIKEL AND t2.SUPPLIERID = t1.SUPPLIERID
),
cumulative AS
(
    SELECT *, SUM(PIECES) OVER (PARTITION BY GroupId ORDER BY ROW_ID) AS CumulativeSum
    FROM cte
)
SELECT ROW_ID, ARTIKEL, SUPPLIERID, ORGID, PIECES, COSTPRICE, DISCOUNT, 
        CASE
            WHEN CumulativeSum < SALE_SUM_PIECES THEN NULL
            WHEN @x - CumulativeSum <= 0 AND @x - (CumulativeSum - PIECES) > 0 THEN 0
            WHEN @x - CumulativeSum <= 0 THEN NULL
            ELSE @x - CumulativeSum
        END AS VALUE_DRILL_DOWN
FROM cumulative

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