SQL數據透視日期列？

Question

我對SQL相當陌生，但相信我在發佈之前已經搜索過幫助。

我有一個查詢，它返回分配給作業的人員列表，這些作業也有不同的長度，分配給這些作業的人員工作的長度不同。

我想要做的是轉換什麼是類似記錄的列表，只有變量的變化是日期，以及一些如何使這些數據轉動，使日期成爲列標題，行代表BOOL是/否。

這是我目前找回的數據。 JSON編碼

{"results":[{"role":"Vision Supervisor","familyname":"Unsworth","givenname":"Simon","skill":"10","level":"Telegenic Staff","id":"664","date":"2013-03-27"},{"role":"Vision Supervisor","familyname":"Unsworth","givenname":"Simon","skill":"10","level":"Telegenic Staff","id":"664","date":"2013-03-26"},{"role":"Vision Supervisor","familyname":"Unsworth","givenname":"Simon","skill":"10","level":"Telegenic Staff","id":"664","date":"2013-03-25"},{"role":"Vision Supervisor","familyname":"Unsworth","givenname":"Simon","skill":"10","level":"Telegenic Staff","id":"664","date":"2013-03-24"}]}

什麼，我想得到的回覆是：

{"results":[{"role":"Vision Supervisor","familyname":"Unsworth","givenname":"Simon","skill":"10","level":"Telegenic Staff","id":"664","2013-03-27":"YES","2013-03-26":"YES","2013-03-25":"YES","2013-03-24":"YES"}]}

我敢肯定，這是某種形式的PIVOT查詢的，但我不能得到它的工作。

感謝

Answer 1

如果你要運行在SQL Server此查詢，那麼你可以使用PIVOT功能：

select * 
from 
(
    select role, familyname, givenname, skill, 
    level, id, date, 'Y' flag 
    from yourtable 
) src 
pivot 
(
    max(flag) 
    for date in ([2013-03-27], [2013-03-26], 
       [2013-03-25], [2013-03-24]) 
) piv 

見SQL Fiddle with Demo

或者你可以使用一個聚合函數和CASE聲明：

select role, familyname, givenname, skill, 
    level, id, 
    max(case when date = '2013-03-27' then flag end) '2013-03-27', 
    max(case when date = '2013-03-26' then flag end) '2013-03-26', 
    max(case when date = '2013-03-25' then flag end) '2013-03-25', 
    max(case when date = '2013-03-24' then flag end) '2013-03-24' 
from 
(
    select role, familyname, givenname, skill, 
    level, id, date, 'Y' flag 
    from yourtable 
) src 
group by role, familyname, givenname, skill, 
    level, id 

見SQL Fiddle with Demo

均可以得到結果：

|    ROLE | FAMILYNAME | GIVENNAME | SKILL |   LEVEL | ID | 2013-03-27 | 2013-03-26 | 2013-03-25 | 2013-03-24 | 
---------------------------------------------------------------------------------------------------------------------------------- 
| Vision Supervisor | Unsworth |  Simon | 10 | Telegenic Staff | 664 |   Y |   Y |   Y |   Y | 

以上的偉大工程，如果你知道移調值，但如果你不這樣做，那麼你可以使用動態SQL與此類似：

DECLARE @cols AS NVARCHAR(MAX), 
    @query AS NVARCHAR(MAX) 

select @cols = STUFF((SELECT ',' + QUOTENAME(convert(char(10), date, 120)) 
        from yourtable 
        group by date 
        order by date desc 
      FOR XML PATH(''), TYPE 
      ).value('.', 'NVARCHAR(MAX)') 
     ,1,1,'') 

set @query = 'SELECT role, familyname, givenname, skill, 
        level, id,' + @cols + ' from 
      (
       select role, familyname, givenname, skill, 
        level, id, date, ''Y'' flag 
       from yourtable 
      ) x 
      pivot 
      (
       max(flag) 
       for date in (' + @cols + ') 
      ) p ' 

execute(@query) 

見SQL Fiddle with Demo