SQL Server error simplify code due to multiple joins - sql

Question

I need an alternative way to simplify this code.
This code computes the age of the balances of the client depending on the repayment schedule of loan. The filters are 1-7 days, 8-30, 31-60 .... and so on until it reach 181 and above
with membersWithLoans as -- gets members with loan
(
select
a.memberid, a.loanid, a.loanamt, a.intamt
from
loanmst a
where
loandt <= '12/19/2016'
and status = 'O'
)
,selectPaymentToDate as -- gets payments of the members to date
(
select
b.loanid, sum(a.princollamt) as princollamt1,
sum(a.intcollamt) as intcollamt1
from
collectiondtl a
inner join
membersWithLoans b on a.loanid = b.loanid
where
a.accdate <= '12/19/2016'
group by
b.loanid)
,selectBalanceToDate as -- gets the balance of member to date
(
select
b.loanid,
sum(a.princeamt) as prinBalanceToDate,
sum(a.instamt) as intBalanceToDate,
sum(a.insamt) as insuBalanceToDate
from
loandtl a
inner join
membersWithLoans b on a.loanid = b.loanid
where
a.duedt <= '12/19/2016'
group by
b.loanid)
, combineBalanceWithpayment as -- combine payment and balance
(
select a.loanid,a.loanamt, a.intamt,
(case
when b.prinBalanceToDate is null then 0
else b.prinBalanceToDate end) as prinBalanceToDate2,
(case
when b.intBalanceToDate is null then 0
else b.intBalanceToDate end) as intBalanceToDate2,
(case
when b.insuBalanceToDate is null then 0
else b.insuBalanceToDate end) as insuBalanceToDate2,
(case
when c.princollamt1 is null then 0
else c.princollamt1 end) as PrincipalCollectiontoDate,
(case
when c.intcollamt1 is null then 0
else c.intcollamt1 end) as IntCollectiontoDate,
cast(((case
when b.prinBalanceToDate is null then 0
else b.prinBalanceToDate
end)
-
(case
when c.princollamt1 is null then 0
else c.princollamt1 end))as decimal(10,2)) as Arrears
from
membersWithLoans a
left join selectBalanceToDate b
on a.loanid=b.loanid
left join selectPaymentToDate c
on a.loanid=c.loanid
)
,filterNegativeArrears as
(
select *
from
combineBalanceWithpayment
where Arrears > 0
)
the code above gets the member information
,select1To7days as -- this code gets amount to be paid in a specific schedule
(
select b.loanid,
sum((case
when a.princeamt is null then 0
else a.princeamt end))as prin7Daysbalance
from loandtl a
inner join membersWithLoans b
on a.loanid=b.loanid
where
a.duedt > DATEADD(day,-7,'12/19/2016')
and
a.duedt<='12/19/2016'
group by b.loanid
)
,select8to30days as -- this code gets amount to be paid in a specific schedule
(
select b.loanid,
sum((case
when a.princeamt is null then 0
else a.princeamt end))as prin8To30Daysbalance
from loandtl a
inner join membersWithLoans b
on a.loanid=b.loanid
where
a.duedt<=DATEADD(day,-7,'12/19/2016')
and a.duedt > DATEADD(day,-30,'12/19/2016')
group by b.loanid
)
-- and so on ..... the filters for schedule is compose of 31 to 60days, 61 to 90 days,
--121 to 180 days, 181 and above. there is no pattern since it the requirement on days may change
, computePar1To7days as -- computes the 1 to 7 days
(
select a.loanid, cast((a.arrears - a.Par1To7days) as decimal(10,2)) as deductedArrears, a.Par1To7days
from
(
select a.loanid,a.arrears,
cast((case
when a.arrears >= b.prin7Daysbalance then b.prin7Daysbalance -- if the arrears is greater than the 7days balance to be collected then it will be show
else a.arrears end)as decimal(10,2))as Par1To7days -- else the remaining is the arrears
from
filterNegativeArrears a
left join select1To7days b
on a.loanid=b.loanid
) a
where cast((a.arrears - a.Par1To7days) as decimal(10,2)) > 0
)
,computePar8To30days as -- computes the 8 to 30 days
(
select a.loanid, cast((a.arrears - a.Par8To30days)as decimal(10,2)) as deductedArrears, a.Par8To30days
from
(
select a.loanid, a.deductedArrears as arrears,
cast((case
when (a.deductedArrears) > 0
then
(case
when (a.deductedArrears)>= b.prin8To30Daysbalance
then b.prin8To30Daysbalance
else (a.deductedArrears)
end)
else 0 end)as decimal(10,2))as Par8To30days
from computePar1To7days a
left join select8To30days b
on a.loanid=b.loanid
) a
where cast((a.arrears - a.Par8To30days) as decimal(10,2)) > 0
)
-- so on until all par is computed. 31 to 60 days, 61 to 90 days,
--121 to 180 days, 181 and above. there is no pattern since it the requirement on days may change
the code above gets the sum of data from specific schedules like
1 to 7 days, 8-30 days, 31 to 60 days, 61 to 90 days, 121 to 180 days, 181 and above
select a.*,
b.Par1To7days,
c.Par8To30days,
d.Par31To60days,
e.Par61To90days,
f.Par91To120days,
g.Par121To180days --,
--h.Par181AndAbovedays
from
filterNegativeArrears a
left join computePar1To7days b
on a.loanid=b.loanid
left join computePar8To30days c
on a.loanid=c.loanid
left join computePar31To60days d
on a.loanid=d.loanid
left join computePar61To90days e
on a.loanid=e.loanid
left join computePar91To120days f
on a.loanid=f.loanid
left join computePar121To180days g
on a.loanid=g.loanid
--left join computePar181AndAbovedays h
-- on a.loanid=h.loanid
the code above joins the computed age
The code is working fine and calculating fine
but when I add more join in the selection I get an error
left join computePar181AndAbovedays h
on a.loanid=h.loanid
The problem is I started encountering the error:
An expression services limit has been reached. Please look for
potentially complex expressions in your query, and try to simplify
them.
I still need more table to join with my query.
Can you suggest ways to simplify this query is highly appreciated

Answer 1

You are obviously running into a limit there and budging that limit will not be possible with the query you have. Follow the advice given in the error message: simplify.
How? Well you have a multitude of CTE's defined. Another way of writing your query is by materializing the CTE's in temporary tables before the actual query and then using the temporary tables instead.
For example, this CTE:
membersWithLoans as -- gets members with loan
(
select a.memberid, a.loanid,a.loanamt,a.intamt
from loanmst a
where loandt<='12/19/2016'
and status = 'O'
)
Can be be materialized to a temporary table:
select a.memberid, a.loanid,a.loanamt,a.intamt
into #membersWithLoans
from loanmst a
where loandt<='12/19/2016'
and status = 'O'
This will create a temporary table #membersWithLoans that can be used in further temporary table creations or in your final query.
To illustrate further, suppose you have materialized all your CTE's to temporary tables, you would have no more WITH clause. You would then finally use the temporary tables in your final SELECT query:
-- create all temporary tables (one of them being #filterNegativeArrears)
select
a.*,
-- the rest of your selections
from
#filterNegativeArrears a
-- the rest of the joined temporary tables
-- the rest of your query (WHERE, ORDER BY etc)