sql里将再也行数据统一为一行,数据用逗号分隔

一.定义表变量

DECLARE @T1 table
(
UserID int ,
UserName nvarchar(50),
CityName nvarchar(50)
);

insert into @T1 (UserID,UserName,CityName) values (1,’a’,’上海’)
insert into @T1 (UserID,UserName,CityName) values (2,’b’,’北京’)
insert into @T1 (UserID,UserName,CityName) values (3,’c’,’上海’)
insert into @T1 (UserID,UserName,CityName) values (4,’d’,’北京’)
insert into @T1 (UserID,UserName,CityName) values (5,’e’,’上海’)

select * from @T1

—–最优的法门
SELECT CityName,STUFF((SELECT ‘,’ + UserName FROM @T1 subTitle WHERE
CityName=A.CityName FOR XML PATH(”)),1, 1, ”) AS A
FROM @T1 A

—-次之种方法

SELECT   CityName ,
                REPLACE(RTRIM(REPLACE(REPLACE(( SELECT  UserName
                                                FROM   
@T1 m
                                                where    m.CityName =
A.CityName
                                                 FOR XML AUTO
                                              ), ‘<m UserName=”‘,
”), ‘”/>’,
                                      ‘ ‘)), ‘ ‘, ‘,’)
       FROM     @T1 A

—-第三种艺术
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(”)),1,1,”)
这一整句的效益是将多行田野先生name字段的始末串联起来,用逗号分隔。

for xml path是SQL Server 二零零六今后版本补助的一种生成XML的主意。

stuff函数的效能是去掉字符串最前方的逗号分隔符。

效果图:

图片 1

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