Question

我有一个公司，行业和company_industry_map多对多表。

company_id | company_name
1            Goldman Sachs
2            Microsoft

industry_id | industry
4             Technology
5             Finance
6             Banking

company_id | industry_id
1            5
1            6
2            4

我想编写一个将所有行业加入逗号分隔列表的查询，如下所示：

company_id | industries
1            Finance, Banking
2            Technology

这是我正在尝试写的一般查询：

SELECT company_id, 
       xxx AS industries 
  FROM company c, 
       company_industry_map m 
 WHERE c.company_id = m.company_id

Answer 1

您可以在SQL Server中使用类似的东西

select co.CompanyID, AllIndustries = 
       (select (cast(industry as varchar(200))+',') as [text()]
       FROM company c, 
       company_industry_map m 
       WHERE c.company_id = m.company_id and c.company_id = co.company_id 
       order by industry_id for XML PATH(''))
from Companies co

Answer 2

在SQL Server中，您可以创建如下函数：

declare @var nvarchar(max)

set @var = ''
select @var = @var  + ',' + UserLogin from [user] 

select @var

SQL Server以逗号分隔列表的形式连接结果

2 个答案: