選擇一組不同的值並將它們分別計入新列

Question

我相當確定這是一件容易的事情，但我是SQL新手，所以要溫和。如果我想編寫一個查詢，將每個進程編號的總髮生次數加起來，並將這些值存儲到新列中，我該怎麼做？我認爲一些混合物（清楚...）可能會把它弄清楚，但我不確定。查看結果表以瞭解我在找什麼。

 
Order_Table: 

order_number  process 
     100   8 
     100   7 
     100   7 
     100   6 
     100   5 
     105   6 
     105   2 
     105   4 

Results: 

order_num NumOfEight NumOfSeven NumOfSix NumOfFive NumOfFour NumOfTwo 
     100    1   2   1   1   0   0 
     105    0   0   1   0   1   1 

更新：我使用SQL 2005作爲基礎，但可以訪問更新的版本。過程是一組有限的值。

Answer 1

假設的SQL Server 2005+可以使用PIVOT

SELECT 
     order_num, [8] AS NumOfEight, [7] AS NumOfSeven /* etc. etc.*/ 
FROM 
     (SELECT order_number AS order_num, process FROM Order_Table) p 
PIVOT 
     (COUNT(process) FOR process IN ([8],[7] /* etc. etc.*/)) pvt 

Answer 2

select order_num, 
     sum(case when process = 8 then 1 else 0 end) as NumOfEight, 
     sum(case when process = 7 then 1 else 0 end) as NumOfSeven, 
     sum(case when process = 6 then 1 else 0 end) as NumOfSix 
     /* Repeat as many times as needed */ 
    from Order_Table 
    group by order_num