Question

我有以下SQL。大多数G1和G2是一对一的关系。一些是一对多的关系。以下SQL将显示太多“ Total2 ”。当G1和G2是一对一时，是否可以删除这些 Total2 行？

SELECT  CASE WHEN GROUPING_ID(G1) = 1 THEN 'Total1' ELSE G1 END,
        CASE WHEN GROUPING_ID(G2) = 1 THEN 'Total2' ELSE G2 END,
        SUM(a),
        SUM(b),
        count(*)
FROM    data
GROUP BY
        G1, G2 WITH ROLLUP

Answer 1

不幸的是，我不知道如何在这里避免使用子查询

使用子查询我们可以使用一个技巧 - 当我们按G1分组并且同时G1和G2具有1对1的关系（即相等）时，意味着max（G2）将等于min（g2）并且这个条件将允许我们构建一个where子句并摆脱它们

代码可能是这样的

select * from
(
SELECT  CASE 
WHEN GROUPING_ID(G1) = 1 THEN 'Total1' ELSE G1 END as G1,    
MIN(g2) as min_g2, 
max(g2) as max_g2,
CASE WHEN GROUPING_ID(G2) = 1 THEN 'Total2' ELSE G2 END as G2,  
       SUM(a) as SUM_A,       
         SUM(b) as SUM_B,       
           count(*) as cnt
FROM    data 
GROUP BY         G1, G2 
WITH ROLLUP 
) t
where 
not (min_g2 = max_g2 and g2 = 'Total2')

SQL Server条件汇总（仅当有多个子组时汇总）

1 个答案: