Question

具有如下表格：

F    G
---- ----
123  ABC
ABC  123
DEF  123

我需要获取：

F    G
---- ----
123  ABC
DEF  123

Answer 1

这是您想要的吗？

select min(f), max(g)
from t
group by (case when f < g then f else g end),
         (case when f < g then g else f end);

Answer 2

假设您有一列，可让您对行进行唯一排序，例如int id或date列，则以下内容应适用：

[Authorize]

Answer 3

此CTE匹配f / g和g / f匹配项（仅保留一个匹配项）和不匹配的并集：

Create Table #tbl
(
F VarChar(10),
G VarChar(10)
)

Insert Into #tbl Values
('123','ABC'),
('ABC','123'),
('DEF','123'),
('123','DEF'),
('123','XYZ')

With CTE As
(
   Select  x.F, x.G, Row_Number() Over (Order By (Select Null)) As rn
   From #tbl x 
   inner Join #tbl y On x.F = y.G And x.G = y.F
) ,
CTE1 As
(
   Select  x.F, x.G
   From #tbl x 
   left Join #tbl y On x.F = y.G And x.G = y.F
   Where y.F  Is Null
)
   Select F,G From CTE Where rn % 2 <> 0 
     Union All 
   Select F,G From CTE1

结果：

F   G
ABC 123
123 DEF
123 XYZ

如何获得列之间的唯一组合？

3 个答案: