Question

是否可以动态更改结果集列顺序？

伪代码示例：

select [city], [state], [country] 
from mystuff
result order 2,1,3

以便结果集

state | city | country
California, LA, US

Answer 1

不，列顺序由SELECT列表确定。如果由于某种原因必须保持完整的查询，则可以将其用作派生表。例如：

SELECT [city], [state], [country]
FROM (fixedquery) as X

Answer 2

您可以尝试如下，它会帮助您...

查询：

Declare @order as varchar(100), @Query varchar(1000), @Query2 varchar(1000)
set @order = 123

While len(@order) > 0
begin
      set @Query = IsNull(@Query,'') + 
                              case substring(@order, 1,1)
                                    when  1 then 'city' 
                                    when  2 then 'state'
                                    when  3 then 'country'
                              end + 
                              Case when len(@order) > 1 then ',' else '' end
      set @order = substring(@order, 2,len(@order))
end

set @Query2 = 'select ' + @Query + ' from mystuff'

Exec (@Query2)

输出

If you give order as 123 then

City -- State -- Country as result    

If you give order as 213 then 

State -- City --Country as result

If you give order as 231 then

State -- Country -- City as result

检查出来......

TSQL：动态更改选择结果列顺序

2 个答案: