Question

我有一张名为industry的表。有6个领域。架构如下。

在这种情况下，我需要执行自定义聚合。数据库中有22个区域。需要进行两次自定义聚合：

区域1-17需要组合成值为00的新区域。
区域20和21需要制作成另一个，代码值为99.

接下来是我尝试的整体框架。我假设创建一个新表是最简单的方法来实现这一点。底部是预期结果的一个非常简短的例子。

 create table industry2
 (
 year char(4),
 qtr char(2),
 area char(6),
 industry char(3),
 ownership char(2),
 employment numeric(8,0)
 );

 INSERT INTO Industry2
 (year, qtr, area, industry, ownership, employment)
 SELECT year, qtr, area, (select sum (employment) from dbo.industry where area 
 = '01' or area = '02' and so on):

 2017    01    01   123000    1    456
 2017    01    02   123000    1    101
 2017    01    03   123000    1    103
 2017    01    01   134000    1      6
 2017    01    02   134000    1      7
 2017    01    03   134000    1     12
 2017    01    09   134000    1      1
 2017    01    01   144000    1     14
 2017    01    20   134000    1      7
 2017    01    21   134000    1      8

预期结果

 2017   01     00   123000    1    660
 2017   01     00   134000    1     26
 2017   01     00   144000    1     14
 2017   01     99   134000    1     15

Answer 1

您可以使用GROUP BY声明定义自定义CASE WHEN子句：

select  [year], 
        [qtr],
        case when [area] in('20','21') then '99' when [area] between 1 and 17 then '00' end as [area], 
        [industry], 
        [ownership], 
        sum([employment]) as [employment_sum] 
from industry2 
group by  
    [year], 
    [qtr], 
    case when [area] in('20','21') then '99' when [area] between 1 and 17 then '00' end, 
    [industry], 
    [ownership]

结果：

SQL中的自定义聚合

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