在SQL Server中创建逗号分隔的结果

Question

  

可能重复：
  Simulating group_concat MySQL function in MS SQL Server 2005?
  Concat field value to string in SQL Server

涉及2个表，用户和关键字。

用户的
用户id
的firstName
lastName的
...

关键字
用户id
关键字

如果我运行此查询：

select u.userId, u.firstName, u.lastName, k.keyword 
from Users as u 
inner join  Keywords as k on u.userId = k.userId

我得到这样的东西：

我想要的是：

This looked very similar to what I wanted但我似乎无法让它正常工作。

Answer 1

SELECT
       u.userId,
       u.firstName,
       u.lastName,
       (select keyword +', ' from Keywords tk where tk.userid= u.userid for xml path ('')  )   as keyword
  FROM
       Users AS u 

要测试的示例查询：

declare @Users as table(
userid int,
firstname varchar(20),
lastname varchar(20)

)

declare @Keywords as table(
userid int,
keyword varchar(20)

)

insert into @Users
values(
1, 'Bob','Sanders'
),
(
2, 'Jamie','Smith'
)

insert into @Keywords
values 
(1,'Cars'),
(1,'Pizza'),
(2,'Tomato'),
(2,'Blah')

SELECT
       u.userId,
       u.firstName,
       u.lastName,
       (select keyword +', ' from @Keywords tk where tk.userid= u.userid for xml path ('')  )   as keyword
  FROM
       @Users AS u 

返回：

userId  firstName   lastName    keyword
1       Bob         Sanders     Cars, Pizza, 
2       Jamie       Smith       Tomato, Blah, 

Answer 2

;WITH a AS (
  SELECT 
    u.userId,
    u.firstName,
    u.lastName,
    ( SELECT k.keyword + ',' 
      FROM Keywords k
      WHERE k.userId = u.userId
      ORDER BY k.keyword
      FOR XML PATH('') 
    ) AS [keyword]
  FROM Users u
)
SELECT 
  a.userId,
  a.firstName,
  a.lastName,
  -- strip off trailing comma
  LEFT(
    a.keyword, 
    LEN(a.keyword)-1
  ) AS keyword
FROM a   

Answer 3

您可以创建一个新的sql聚合函数concat来连接文本并在查询中使用if：

select userId, firstName, Lastname, concat(Keyword)
from Users
group by userId, firstName, Lastname;

Follwoing链接显示了如何创建concat功能的示例。 http://msdn.microsoft.com/en-us/library/ms182741.aspx