Complexity Of Nested Self Left Joins?

Hi,

I'm curious about the computational complexity of a query I have. The
query contains multiple nested self left joins, starting with a simple
select, then doing a self left join with the results, then doing a self
left join with those results, etc. What puzzles me is that the time
required for the query seems to grow exponentially as I add additional
left joins, which I didn't expect. I expected the inner select to
return about 25 rows (it does), then I expected the self join to result
in about 25 rows (it does), etc. Each join just adds another column; it
doesn't add more rows. So the left part of the join is staying the same
size, and so is the right part of the join, since I'm always joining
with the same table.

So I would think the time for this query should be (time to join 25
rows against the source table) * (num joins), but it seems to be
something like (num rows) ^ (num joins). Any ideas? I'm just trying to
understand the system a little better. (But if you have any ideas about
improving the query, I'm always open to those, too.)

The execution plan is what you'd expect: an index seek loop-joined with
another index seek, the results of which are merge-joined with another
index seek, the results of which are merge-joined with another index
seek, ad nauseum, until a final "compute scalar cost (39%)" and "select
(0%)"

For the brave and curious, I've pasted the query below.

Thanks

select right(x.cp_yyyymm, 2)+'-'+left(x.cp_yyyymm, 4) as [Month],
table0.cp_num_loans/1 as [AFCM9704], table1.cp_num_loans/1 as
[AFC9104], table2.cp_num_loans/1 as [BFAT01C], table3.cp_num_loans/1 as
[BFAT02B], table4.cp_num_loans/1 as [BFAT03D], table5.cp_num_loans/1 as
[BFAT03E], table6.cp_num_loans/1 as [BFAT03F], table7.cp_num_loans/1 as
[BFAT04A], table8.cp_num_loans/1 as [BFAT04C], table9.cp_num_loans/1 as
[BFAT04D], table10.cp_num_loans/1 as [BFAT99C] from (((((((((((select
distinct cp_yyyymm from cp_deal_history where cp_deal_id in
('AFCM9704', 'AFC9104', 'BFAT01C', 'BFAT02B', 'BFAT03D', 'BFAT03E',
'BFAT03F', 'BFAT04A', 'BFAT04C', 'BFAT04D', 'BFAT99C') and cp_yyyymm
between 200304 and 200504) as x left join (select cp_yyyymm,
cp_num_loans from cp_deal_history where cp_deal_id='AFCM9704') as
table0 on x.cp_yyyymm=table0.cp_yyyymm) left join (select cp_yyyymm,
cp_num_loans from cp_deal_history where cp_deal_id='AFC9104') as table1
on x.cp_yyyymm=table1.cp_yyyymm) left join (select cp_yyyymm,
cp_num_loans from cp_deal_history where cp_deal_id='BFAT01C') as table2
on x.cp_yyyymm=table2.cp_yyyymm) left join (select cp_yyyymm,
cp_num_loans from cp_deal_history where cp_deal_id='BFAT02B') as table3
on x.cp_yyyymm=table3.cp_yyyymm) left join (select cp_yyyymm,
cp_num_loans from cp_deal_history where cp_deal_id='BFAT03D') as table4
on x.cp_yyyymm=table4.cp_yyyymm) left join (select cp_yyyymm,
cp_num_loans from cp_deal_history where cp_deal_id='BFAT03E') as table5
on x.cp_yyyymm=table5.cp_yyyymm) left join (select cp_yyyymm,
cp_num_loans from cp_deal_history where cp_deal_id='BFAT03F') as table6
on x.cp_yyyymm=table6.cp_yyyymm) left join (select cp_yyyymm,
cp_num_loans from cp_deal_history where cp_deal_id='BFAT04A') as table7
on x.cp_yyyymm=table7.cp_yyyymm) left join (select cp_yyyymm,
cp_num_loans from cp_deal_history where cp_deal_id='BFAT04C') as table8
on x.cp_yyyymm=table8.cp_yyyymm) left join (select cp_yyyymm,
cp_num_loans from cp_deal_history where cp_deal_id='BFAT04D') as table9
on x.cp_yyyymm=table9.cp_yyyymm) left join (select cp_yyyymm,
cp_num_loans from cp_deal_history where cp_deal_id='BFAT99C') as
table10 on x.cp_yyyymm=table10.cp_yyyymm order by x.cp_yyyymm