Вам нужно отсортировать по id1, id2 и id3
РЕДАКТИРОВАТЬ: Обновлено с дополнительным полем последовательности
;WITH data AS
(
select id1,c1,id2,c2,id3,c3,
ROW_NUMBER() OVER (PARTITION BY id1, id2 ORDER BY id2) as id2seq,
ROW_NUMBER() OVER (PARTITION BY id1, id2, id3 ORDER BY id3) as id3seq
from t1
left join t2 on t2.fk = t1.pk
left join t3 on t3.fk = t1.pk
)
select id1, c1, id2, c2, id3, c3
from data
order by id1, id2seq, id3seq
РЕДАКТИРОВАТЬ : Завершенный запрос для точных результатов
;with data as(
select pid
, pname
, cid
, cname
from #t1 t1
left join #t2 t2 on t2.fk_pid = t1.pid
), cte AS
(
select pid
, eid
, ename
from #t1 t1
left join #t3 t3 on t3.fk_pid = t1.pid
), combine AS
(
select d.pid
, pname
, cid
, cname
, ROW_NUMBER() over(partition by d.pid, cid order by cid) as seq
, eid
, ename
from data d join cte c on d.pid = c.pid
)
select pid, pname, cid, cname, eid, ename
from combine
order by pid, seq, cid