declare @a varchar(max)

select @a = coalesce(@a,  '', '') + ',' + cast(t.XRecID as varchar) from
	(select TaskID from SBTaskAttach where AttachID=34974738) att
join 
	(select xrecid, Subject, StandardRoute from SBTask where StandardRoute not in (24154818, 36257438, 4383004, 20394678, 33665941, 859568, 28612983)) t
on att.TaskID = t.XRecID

select right(@a, len(@a)-1), attachID from SBTaskAttach

select a.attachID, (
	select cast(TaskID as varchar) + ','
	from SBTaskAttach as att 
	join 
		(select xrecid from SBTask where StandardRoute not in (24154818, 36257438, 4383004, 20394678, 33665941, 859568, 28612983)) t
	on att.TaskID = t.XRecID
	where att.AttachID = a.AttachID
	for xml path(''))
from SBTaskAttach a
where AttachID = 34974738