如何將單個整數值列拆分爲n列？

Question

我有一個SQL Server表表名，如：

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

我要像下面

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 

如何從SQL服務器查詢此輸出得到輸出。

Answer 1

如果你想要的輸出，你甚至都不需要啓動一個表：

with cte as (
     select 1 as col1, 2 as col2, 3 as col3, 4 as col4, 5 as col5 
     union all 
     select 5 + col1, 5 + col2, 5 + col3, 5 + col4, 5 + col5 
     from cte 
     where 5 + col1 <= 15 
    ) 
select * 
from cte; 

Answer 2

假設你的表不只是擁有1連續編號爲n（如果這樣做，戈登的回答是更好）， 這裏是做這件事：

首先，創建和填充示例表（請保存這一步是在你未來的問題）

SELECT TOP 100 IDENTITY(int,1,1) AS col1 
    INTO table_name 
    FROM sys.objects s1  
    CROSS JOIN sys.objects s2 


DELETE 
FROM table_name 
WHERE col1 IN 
(
    SELECT TOP 67 col1 
    FROM table_name 
    ORDER BY NEWID() 
) 

（TABLE_NAME現在包含1到100之間33張隨機數）

使用一對夫婦的公共表表達式來獲取列數和行號：

;With Cols as 
(
    SELECT col1, 
      ROW_NUMBER() OVER(ORDER BY col1) % 5 ColNumber 
    FROM table_name 
), RowsAndCols as 
(
    SELECT col1, ColNumber, ROW_NUMBER() OVER(PARTITION BY ColNumber ORDER BY col1) As RowNumber 
    FROM Cols 
) 

和查詢：

SELECT c1.col1, c2.col1 As col2, c3.col1 As col3, c4.col1 As col4, c5.col1 As col5 
FROM RowsAndCols c1 
LEFT JOIN RowsAndCols c2 ON c1.RowNumber = c2.RowNumber AND c2.ColNumber = 2 
LEFT JOIN RowsAndCols c3 ON c1.RowNumber = c3.RowNumber AND c3.ColNumber = 3 
LEFT JOIN RowsAndCols c4 ON c1.RowNumber = c4.RowNumber AND c4.ColNumber = 4 
LEFT JOIN RowsAndCols c5 ON c1.RowNumber = c5.RowNumber AND c5.ColNumber = 0 
WHERE c1.ColNumber = 1 

注意我使用了左連接，所以萬一行數不是5的倍數，你會在最後一行的最後一列得到空值。

See a live demo on rexteser.

Answer 3

使用基於把一個row_number()，以及用於列放置使用modulo %條件聚合：

測試設置：

select n into dbo.numbers from (values 
    (1), (2), (3), (4), (5), (6), (7), (8), (9),(10) 
,(11),(12),(13),(14),(15),(16),(17),(18),(19),(20) 
) t(n) 
delete from dbo.numbers where n in (12,13,17); 

查詢：

select 
    col1 = sum(case when rn%5=0 then n end) 
    , col2 = sum(case when rn%5=1 then n end) 
    , col3 = sum(case when rn%5=2 then n end) 
    , col4 = sum(case when rn%5=3 then n end) 
    , col5 = sum(case when rn%5=4 then n end) 
from (
    select n, rn = row_number() over (order by n)-1 
    from dbo.numbers 
) t 
group by rn/5; 

rextester演示：http://rextester.com/UHKY16981個

回報：

+------+------+------+------+------+ 
| col1 | col2 | col3 | col4 | col5 | 
+------+------+------+------+------+ 
| 1 | 2 | 3 | 4 | 5 | 
| 6 | 7 | 8 | 9 | 10 | 
| 11 | 14 | 15 | 16 | 18 | 
| 19 | 20 | NULL | NULL | NULL | 
+------+------+------+------+------+ 

---

同樣的概念，但使用pivot()代替條件聚集返回相同的結果。

select 
    col1 = [0] 
    , col2 = [1] 
    , col3 = [2] 
    , col4 = [3] 
    , col5 = [4] 
from (
    select n 
    , rn = (row_number() over (order by n)-1)%5 
    , grp = (row_number() over (order by n)-1)/5 
    from dbo.numbers 
) t 
pivot (sum(n) for rn in ([0],[1],[2],[3],[4])) p; 

Answer 4

另一種選擇是Dynamic Pivot。

這將創建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，則結果是：

編輯全參數驅動版本

這個版本可以提供

1. 列數@NbrCols（同上）
2. 來源@FromSrc，這是表名或SQL字符串中的（）即(Select ...)
3. 列名@ColName [透視@ColName
4. 的科拉姆前綴@ColPrfx即'Col-'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