如何将单个整数值列拆分为n列？

Question

我有一个SQL Server表table_name,如:

col1   
1
2
3
4
5
6
7
8
9
.
.
.
N

我想要如下输出

col-1 | col-2 | col-3 | col-4 |col-5
-------------------------------
1     | 2     | 3     | 4     |5
6     | 7     | 8     | 9     |10
11    | 12    | 13    | 14    |15

如何从sql-server查询中获取此输出.

Answer 1

另一种选择是Dynamic Pivot.

这将创建N列.

例

Declare @nCols int  = 5

Declare @SQL varchar(max) = '
Declare @nCols int = '+str(@nCols,5)+'
Select *
 From (
        Select RowNr = ((row_number() over (order by col1)-1)/@nCols)+1
              ,ColNr = concat(''col-'',isnull(nullif((row_number() over (order by col1))%@nCols,0),@nCols))
              ,Value = col1
         From YourTable
      ) A
 Pivot (max(Value) For ColNr in (' + Stuff((Select Top (@nCols) ','+QuoteName(concat('col-',Row_Number() Over (Order By (Select NULL)))) From  YourTable For XML Path('')) ,1,1,'') + ') ) p'
Exec(@SQL);
--Print @SQL

返回

如果@nCols = 3,结果为:

编辑完全参数驱动的版本

这个版本你可以提供

1. 列数@NbrCols(与上面相同)
2. Source @FromSrc,即()中的表名或SQL String(Select ...)
3. 列名称@ColName为Pivot@ColName
4. colum前缀@ColPrfx ie 'Col-'或甚至''

Declare @NbrCols int  = 5
Declare @FromSrc varchar(max) = 'YourTable'  -- Or SQL '(Select col ...)'
Declare @ColName varchar(100) = 'col1'
Declare @ColPrfx varchar(100) = 'Col-'

Declare @SQL varchar(max) = '
Declare @NbrCols int = '+str(@NbrCols,5)+'
Select *
 From (
        Select Row = ((row_number() over (order by '+quotename(@ColName)+')-1)/@NbrCols)+1
              ,Col = concat('''+@ColPrfx+''',isnull(nullif((row_number() over (order by '+quotename(@ColName)+'))%@NbrCols,0),@NbrCols))
              ,Val = '+quotename(@ColName)+'
         From '+@FromSrc+' A1
      ) A
 Pivot (max(Val) For Col in (' + Stuff((Select Top (@NbrCols) ','+QuoteName(concat(@ColPrfx,Row_Number() Over (Order By (Select NULL)))) From master..spt_values For XML Path('')) ,1,1,'') + ') ) p'
Exec(@SQL);
--Print @SQL