SQL Join Query - Group By/Aggregation

Question

我意識到這個問題之前已經以多種形式提出過，但我很努力地將我找到的每一個答案應用到我的具體表格。開始 - 直接看細節。

表A有四列（唯一ID，數字，版本，日期）。當從A執行選擇*，結果集如下 -

ID | Number | Revision | Date 
------------------------------------ 
01 | 12345 | 1  | 01/01/2010 
02 | 12345 | 2  | 01/04/2010 
03 | 123 | 1  | 01/12/2010 
04 | 1234 | 1  | 09/09/2012 
05 | 12345 | 3  | 09/12/2012 

我想每個修訂的日期在每數量的單個行，例如對於數字12345，查詢將返回

ID | Number | Revision | Date | Revision 2 | Revision 2 Date | Revision 3 | Revision 3 Date | 
--------------------------------------------------------------------------------------------- 
01 | 12345 | 1 | 01/01/2010 |2 | 01/04/2010  | 3 | 09/12/2012| 

我理解語法將類似於

SELECT Revision, Date 
FROM (
SELECT NUMBER 
FROM A) as B INNER JOIN ON a.Number = B.Number 
GROUP BY a.Number 

然而，這仍然返回一行每種組合，我只想上面顯示的結果。

我將不勝感激任何建議或提示！

Answer 1

您可以同時使用UNPIVOT，然後使用PIVOT來完成此操作。如果你有一個已知數量的值轉換爲列，那麼你可以使用一個靜態PIVOT和硬編碼的值：

select number, [revision_1], [date_1], 
      [revision_2], [date_2], 
      [revision_3], [date_3] 
from 
(
    select number, value, 
    col + '_' + cast(rn as varchar(10)) col 
    from 
    (
    select id, number, cast(revision as varchar(10)) revision, 
     convert(varchar(10), date, 120) date, 
     row_number() over(partition by number order by date) rn 
    from yourtable 
) x 
    unpivot 
    (
    value 
    for col in (revision, date) 
) u 
) x1 
pivot 
(
    max(value) 
    for col in ([revision_1], [date_1], 
      [revision_2], [date_2], 
      [revision_3], [date_3]) 
)p 

見SQL Fiddle with Demo

如果你有一個未知數量的值，然後你將需要使用動態SQL來獲取數據。

DECLARE @query AS NVARCHAR(MAX), 
    @colsPivot as NVARCHAR(MAX) 


select @colsPivot = STUFF((SELECT ',' 
         + quotename(c.name + '_' 
         + cast(t.rn as varchar(10))) 
        from 
        (
         select row_number() 
         over(partition by number order by date) rn 
         from yourtable 
        ) t 
        cross apply 
         sys.columns as C 
        where C.object_id = object_id('yourtable') and 
         C.name in ('Revision', 'date') 
        group by c.name, t.rn 
        order by t.rn 
      FOR XML PATH(''), TYPE 
      ).value('.', 'NVARCHAR(MAX)') 
     ,1,1,'') 

set @query 
    = 'select * 
     from 
     (
      select number, value, 
      col + ''_'' + cast(rn as varchar(10)) col 
     from 
     (
      select id, number, cast(revision as varchar(10)) revision, 
      convert(varchar(10), date, 120) date, 
      row_number() over(partition by number order by date) rn 
      from yourtable 
     ) x 
     unpivot 
     (
      value 
      for col in (revision, date) 
     ) u 
    ) x1 
     pivot 
     (
     max(value) 
     for col in ('+ @colspivot +') 
    ) p' 

exec(@query) 

見SQL Fiddle With demo