SQL,关于加入的问题

Question

我在sql 2012中有两个表:name和prod with structure:

名称:id int increment, name1 nvarchar(50)

刺激:id int increment, products nvarchar(50), id_name int

表的值是:

名称表:

Id   name1
1    pop
2    andi

产品表:

Id   products   id_name
1    coke       1
2    pizza      1
3    orange     2

我做了这个查询:

select name.name1, prod.product, prod.id_name
from name
join prod on name.id=prod.id_name

我怎样才能获得这个结果:

pop ->coke, pizza
andi->orange  

Answer 1

遗憾的是,在SQL Server中没有简单的方法.已知的解决方案是:

• xml技巧(见下文);
• 使用变量来累积数据(不适用于多个组行,只能使用游标);
• 自定义CLR聚合;

这是xml:

select
    n.name1,
    stuff(
        (
         select ', ' + p.product
         from prod as p
         where p.id_name = n.id
         for xml path(''),  type).value('.', 'nvarchar(max)')
    , 1, 2, '') as products
from name as n

sql fiddle demo

这是变量:

declare @product nvarchar(max), @id int

select @id = 1

select @product = isnull(@product + ', ', '') + product
from prod
where id_name = @id

select name1, @product as products
from name 
where id = @id

sql fiddle demo