将两个分组查询合并为一个选择答案

【问题标题】：Combine two grouped query into one select将两个分组查询合并为一个选择
【发布时间】：2016-07-26 21:01:30
【问题描述】：

如何连接两个分组在下面的查询？

select [Fiscal Year],[Fiscal Quater],sum([colX])as X
from table1
group by [Fiscal Year],[Fiscal Quater];

select [Fiscal Year],[Fiscal Quater],sum([colY]) as Y
from table2
group by [Fiscal Year],[Fiscal Quater];

结果应该返回列： [财政年度],[财政季度], X, Y

【问题讨论】：

如何连接？向我们展示单独结果的样本以及组合结果。
刚刚更新的问题：FY、FQ、X、Y
This 可能会有所帮助，他们尝试了类似的方法。

标签： sql sql-server sql-server-2008 group-by

【解决方案1】：

UNION ALL 将两个表放在一个派生表中，在主级别执行GROUP BY：

select [Fiscal Year], [Fiscal Quater], sum([colX])as X, sum([colY]) as Y
from
(
select [Fiscal Year], [Fiscal Quater], colX, NULL as colY from table1
UNION ALL
select [Fiscal Year], [Fiscal Quater], NULL as colX, colY from table2
)
group by [Fiscal Year],[Fiscal Quater]

或者，做双重GROUP BY：

select [Fiscal Year], [Fiscal Quater], sum(X), sum(Y) 
from
(
    select [Fiscal Year], [Fiscal Quater], sum([colX]) as X, NULL as Y
    from table1
    group by [Fiscal Year],[Fiscal Quater];
    UNION ALL
    select [Fiscal Year], [Fiscal Quater], NULL as X, sum([colY]) as Y
    from table2
    group by [Fiscal Year],[Fiscal Quater]
)
group by [Fiscal Year],[Fiscal Quater]

也许优化不同？

【讨论】：

【解决方案2】：

你可能想要这样的东西：

select coalesce(t1.[Fiscal Year], t2.[Fiscal Year]) as [Fiscal Year], 
       coalesce(t1.[Fiscal Quater], t2.[Fiscal Quater]) as [Fiscal Quater],
       coalesce(t1.X, 0) as X, 
       coalesce(t2.Y, 0) as Y
from (
  select [Fiscal Year], [Fiscal Quater], sum([colX]) as X
  from table1
  group by [Fiscal Year], [Fiscal Quater]) as t1
full join (
  select [Fiscal Year], [Fiscal Quater], sum([colY]) as Y
  from table2
  group by [Fiscal Year], [Fiscal Quater]
) as t2 on t1.[Fiscal Year] = t2.[Fiscal Year] and 
           t1.[Fiscal Quater] = t2.[Fiscal Quater]

【讨论】：

可以再增加一列，显示上一年的X值吗？
column Fiscal Year 是 Varchar 类型

【解决方案3】：

您可以使用以下 CTE：

WITH T1 AS
(
    SELECT [Fiscal year], [Fiscal  quater], Value = colX FROM   table1 
),
T2 AS
(
    SELECT [Fiscal year], [Fiscal quater], Value = colY FROM   table2
)
SELECT [T1.Fiscal Year],[T1.Fiscal Quater],
       X = SUM(T1.Value),
       Y = SUM(T2.Value)
FROM T1 FULL OUTER JOIN T2
    ON T1.[Fiscal year]   = T2.[Fiscal year] 
   AND T1.[Fiscal quater] = T2.[Fiscal quater] 
GROUP  BY [T1.Fiscal Year], T1.[Fiscal quater]

【讨论】：