sql：把多列的数据转成行的一个字段

select 

    filename, 

    [values]=stuff((select ','+ltrim(serverTypeName)

                    from dbo.V_ItemRule v 

                    where  ProjectId = (select ProjectId from Version
        where VersionId = 
        (select VersionId from IssueTask
        where Id = t.taskid)) and
v.itemname = t.[filename] for xml path('')
), 1, 1, '') 
from TaskAffix t
where taskid = 6917