dawei
一.定义表变量
<div class=”codetitle”><a style=”CURSOR: pointer” data=”75855″ class=”copybut” id=”copybut75855″ onclick=”doCopy(‘code75855’)”> 代码如下:<div class=”codebody” id=”code75855″>
DECLARE @T1 table
(
UserID int,
UserName nvarchar(50),
CityName nvarchar(50)
);
<div class=”codetitle”><a style=”CURSOR: pointer” data=”67569″ class=”copybut” id=”copybut67569″ onclick=”doCopy(‘code67569’)”> 代码如下:<div class=”codebody” id=”code67569″>
insert into @T1 (UserID,UserName,CityName) values (1,’a’,’上海’)
insert into @T1 (UserID,CityName) values (2,’b’,’北京’)
insert into @T1 (UserID,CityName) values (3,’c’,CityName) values (4,’d’,CityName) values (5,’e’,’上海’)
<div class=”codetitle”><a style=”CURSOR: pointer” data=”45543″ class=”copybut” id=”copybut45543″ onclick=”doCopy(‘code45543’)”> 代码如下:<div class=”codebody” id=”code45543″>
select * from @T1
—–最优的方式
SELECT CityName,STUFF((SELECT ‘,’ + UserName FROM @T1 subTitle WHERE CityName=A.CityName FOR XML PATH(”)),1,”) AS A
FROM @T1 A
GROUP BY CityName
—-第二种方式
SELECT B.CityName,LEFT(UserList,LEN(UserList)-1)
FROM (
SELECT CityName,(SELECT UserName+’,’ FROM @T1 WHERE CityName=A.CityName FOR XML PATH(”)) AS UserList
FROM @T1 A
GROUP BY CityName
) B
stuff(select ‘,’ + fieldname from tablename for xml path(”)),”)
这一整句的作用是将多行fieldname字段的内容串联起来，用逗号分隔。
for xml path是SQL Server 2005以后版本支持的一种生成XML的方式。
stuff函数的作用是去掉字符串最前面的逗号分隔符。
效果图：
