sql将行转换为sql server 2008r2中的列

Question

我有一张名为customer,hobby的桌子.顾客有几个爱好.因此,如果我加入我的桌面客户与桌面爱好,我会得到如下结果:

[CustomerName]    [HobbyName]
Harry              Tennis
Harry              Football

我想要的是看到这样的结果:

[CustomerName]    [HobbyName1]    [HobbyName2]
Harry              Tennis           Football

我当前的查询如下所示:

  Select tCustomer.name, tHobby.name 
    from dbo.customer    tCustomer
    inner join dbo.hobby tHobby on tHobby.customerid = tCustomer.id

Answer 1

您没有提供有关表结构的许多详细信息,但您可以使用PIVOT获取最终结果,但为了使用它,您首先要使用row_number()为每个客户的每个爱好生成一个唯一的序列:

select customer, Hobby1, Hobby2
from
(
  Select c.name customer, 
    h.name hobby,
    'Hobby'+
      cast(row_number() over(partition by c.id 
                             order by h.name) as varchar(10)) seq
  from dbo.customer c
  inner join dbo.hobby h 
    on h.customerid = c.id
) d
pivot
(
  max(hobby)
  for seq in (hobby1, Hobby2)
) piv;

请参阅SQL Fiddle with Demo.如果您不想使用PIVOT函数,那么您还可以使用CASE表达式和聚合函数:

select customer,
  max(case when seq = 1 then hobby end) hobby1,
  max(case when seq = 2 then hobby end) hobby2
from
(
  Select c.name customer, 
    h.name hobby,
    row_number() over(partition by c.id 
                      order by h.name) seq
  from dbo.customer c
  inner join dbo.hobby h 
    on h.customerid = c.id
) d
group by customer;

请参阅SQL Fiddle with Demo