Question

我有两个看起来像这样的结果集：

Id       Name    Count
1        Asd     1  
2        Sdf     4    
3        Dfg     567    
4        Fgh     23

但是第二个的Count列数据不同，我希望两者都显示出来，就像这样：

Id       Name    Count from set 1    Count from set two
1        Asd     1                   15
2        Sdf     4                   840
3        Dfg     567                 81
4        Fgh     23                  9

如何在SQL中执行此操作（如果可能，使用union）？我目前的SQL，希望这能更好地解释我想做的事情：

(SELECT Id, Name, COUNT(*) FROM Customers where X)
union
(SELECT Id, Name, COUNT(*) FROM Customers where Y)

Answer 1

您可以执行以下操作：

;WITH Unioned
AS
(
    SELECT 'Set1' FromWhat, Id, Name FROM Table1
    UNION ALL
    SELECT 'Set2', Id, Name FROM Table2
)
SELECT 
  Id, 
  Name,
  SUM(CASE FromWhat WHEN 'Set1' THEN 1 ELSE 0 END) 'Count from set 1',
  SUM(CASE FromWhat WHEN 'Set2' THEN 1 ELSE 0 END) 'Count from set 2'
FROM Unioned
GROUP BY Id, Name;

SQL Fiddle Demo

Answer 2

select * 
from
(
    SELECT 'S1' as dataset, Id, Name, COUNT(*) as resultcount FROM Customers where X
    union
    SELECT 'S2',Id, Name, COUNT(*) FROM Customers where Y
) s
pivot
(sum(resultcount) for dataset in (s1,s2)) p

SQL联合列数相同，数据类型相同，数据不同

2 个答案:

SQL Fiddle Demo