连接一列SQL的行

Question

我正在使用以下查询来提取约会数据:

SELECT app.subject, AL.locationName
FROM FilteredAppointment app
INNER JOIN appointmentlocation AL ON app.activityid = AL.appointment
WHERE app.scheduledstart='2013-07-06 15:00:00.000'

输出如下,有2行(具有两个不同位置的相同约会):

如何修改此查询以仅显示一行,其中两个位置与逗号连接,如下所示:

Column1:(MZN; OTV)*...
Column2:Room1,Room2

谢谢

Answer 1

你需要的是SQL Join和连接行,关于它有很多问题.在SQL Server中没有简单的方法可以做到这一点,但这里有一些技巧:

通过使用select for xml进行连接

select
    app.subject,
    stuff(
       (
           select ', ' + AL.locationName
           from appointmentlocation as AL
           where AL.appointment = app.activityid
           for xml path(''), type
       ).value('.', 'nvarchar(max)')
    , 1, 2, '') 
from FilteredAppointment as app
where app.scheduledstart='2013-07-06 15:00:00.000'

如果您只有一条来自FilteredAppointment的记录要连接,您可以使用聚合到变量:

declare @locations nvarchar(max), @activityid int

select @activityid = ???

select @locations = isnull(@locations + ', ', '') + AL.locationName
from appointmentlocation as AL
where AL.appointment = @activityid

print @locations