Есть запрос типа

SELECT getdate() DateEdit,
case
when not exists (select sm.DezID from g_Order sm where sm.RegID = b.RegID AND sm.Registrate=b.Registrate and sm.ItemID=b.ItemID)
and (b.ItemID in (3,4,6))
then (select sm.DezID from mt_objects sm where sm.RegID = b.RegID AND sm.Registrate=b.Registrate and sm.EffID=1)
when not exists (select sm.DezID from g_Order sm where sm.RegID = b.RegID AND sm.Registrate=b.Registrate and sm.ItemID=b.ItemID)
and (b.ItemID in (18,19))
then (select sm.DezID from mt_objects sm where sm.RegID = b.RegID AND sm.Registrate=b.Registrate and sm.EffID=4)
else
(select sm.DezID from g_Order sm where sm.RegID = b.RegID AND sm.Registrate=b.Registrate and sm.ItemID=b.ItemID)
end as DezID,
case
when not exists (select sm.doc_no from g_Order sm where sm.RegID = b.RegID AND sm.Registrate=b.Registrate and sm.ItemID=b.ItemID)
and (b.ItemID in (33,44,61))
then (select sm.doc_no from mt_objects sm where sm.RegID = b.RegID AND sm.Registrate=b.Registrate and sm.EffID=1)
when not exists (select sm.doc_no from g_Order sm where sm.RegID = b.RegID AND sm.Registrate=b.Registrate and sm.ItemID=b.ItemID)
and (b.ItemID in (1804,1904))
then (select sm.doc_no from mt_objects sm where sm.RegID = b.RegID AND sm.Registrate=b.Registrate and sm.EffID=4)
else
(select sm.doc_no from g_Order sm where sm.RegID = b.RegID AND sm.Registrate=b.Registrate and sm.ItemID=b.ItemID)
end as doc_no,
orderNum.ID,orderNum.RegID, orderNum.Registrate,
(select s.ServiceID from ServiceTypes s where s.ItemID=b.ItemID),
round(b.older_num/1000,2) as NSUMM1,round(b.InitPart/1000,2) as NSUMM2
FROM (select distinct c.doc_no, c.ID, c.RegID, c.Registrate from Init a, mt_objects c where c.DID=14337
and a.RegID = c.RegID AND a.Registrate=c.Registrate
and a.DateBegin<='10.01.2002'
and a.DateEndFact>'10.02.2002'
AND a.resultid in (1,2) and a.statusid=1 and a.dotypeid<9 and a.ID=56) as orderNum,
rt_xecute b
WHERE orderNum.RegID = b.RegID AND orderNum.Registrate=b.Registrate and not b.ItemID in (12,17)
and b.older_num<>0 and b.InitPart<>0
ORDER BY doc_no

исполняющийся на 6.5 версии SQL Server. При исполнении естественно ругается на количество таблиц (>16), учавствующих в запросе.
Каким либо образом можно обойти ограничение без глобального переписования с использованием вьюшек и временных таблиц