TSQL合并和分组值

Question

我有这个sql结果

color    red     AA
color    red     BB
color    red     CC
color    blue    DD
color    blue    EE

有没有办法按列合并,以获得以下结果？

color    red     AA
                 BB
                 CC
         blue    DD
                 EE

Answer 1

这通常是您在应用程序的表示层上执行的操作,但如果要在SQL中执行此操作,则可以使用row_number():

select 
  case when col1rn = 1 then col1 else '' end col1,
  case when col2rn = 1 then col2 else '' end col2,
  col3
from
(
  select col1, col2, col3,
    row_number() over(partition by col1 order by col1, col2, col3) col1rn,
    row_number() over(partition by col1, col2 order by col1, col2, col3) col2rn
  from yt
) d;

请参阅SQL Fiddle with Demo.您将替换from yt您的查询,给出结果:

|  COL1 | COL2 | COL3 |
-----------------------
| color | blue |   DD |
|       |      |   EE |
|       |  red |   AA |
|       |      |   BB |
|       |      |   CC |
|  test | blue |   CC |
|       |  red |   AA |
|       |      |   BB |