如何在SQL Server中進行格式化

Question

在SQL Server 2008中，我有一個查詢。當我使用select查詢我的Student表，我得到一個結果集是這樣的：

Total Subject   Class 
20  Chemistry   Standard -12 
30  Physics   Standard -12 
94  Biology   Standard -12 
0   Maths    Standard -12 

5  Chemistry   Standard -11 
45  Physics   Standard -11 
50  Biology   Standard -11 
45  Maths    Standard -11 

但現在我的要求是，我需要以不同的方式進行格式化 - 這樣的：

    Chemistry Biology Physics Maths 
Standard - 12  20  94  30  0 
Standard - 11  5  50  45  45 

Answer 1

我相信你有獨特的排課和主題組合。

在這種情況下，你可以使用下面的查詢 -

select class, 
     max(case 
      when subject = 'Chemistry' then 
       total 
      else 
       0 
      end) as Chemistry, 
     max(case 
      when subject = 'Biology' then 
       total 
      else 
       0 
      end) as Biology, 
     max(case 
      when subject = 'Physics' then 
       total 
      else 
       0 
      end) as Physics, 
     max(case 
      when subject = 'Maths' then 
       total 
      else 
       0 
      end) as Maths 
    from your_table_name 
group by class 

Answer 2

查詢：

SQLFIDDLEExample

SELECT * 
FROM (SELECT Class, 
     Subject, 
     Total 
     FROM Student) s 
pivot (SUM(Total) 
     FOR [Subject] IN ([Chemistry], [Physics], [Biology], [Maths]) 
     ) piv 

結果：

|  CLASS | CHEMISTRY | PHYSICS | BIOLOGY | MATHS | 
-------------------------------------------------------- 
| Standard -11 |   5 |  45 |  50 | 45 | 
| Standard -12 |  20 |  30 |  94 |  0 |