SQL使用for xml path 多行合并为一行

select

GroupNum,Type,

stuff(

(select ','+Name

from ProjectRelation rela

left join  AccountMedia media on media.id=rela.AccountMediaID

where rela.GroupNum = relamain.GroupNum and rela.Type = relamain.Type and rela.ProjectID = relamain.ProjectID

for xml path('')), 1, 1, '')as 'AccountMedias'  

from ProjectRelation relamain
where ProjectID = 7 group by GroupNum,Type,ProjectID