Comparing sum from two tables and correct by difference of sum in second t,

Question

Hello Guys,
I have a very tricky task that I cant get my head around.
The sample data looks like that:
Master Table
Claim------Booking--------Debit--------Credit------------MasterAmout          
1------------1----------------D---------------------------------15.3          
1------------2----------------D---------------------------------480.6          
1------------3------------------------------C-------------------496.8          
------------------------------------------- 0.9          
Slave Table
Claim-----Booking-----Debit------------Credit----------SlaveAmout------- SlaveCorrection
1------------1------------D------------------------------------15.3---------------14.5
1------------2------------D------------------------------------480.6-------------480.6
1------------3-----------------------------C-------------------496---------------496
-------------------------------------------0.1--------------------------------------0.9
The booking have a total amout of 0.1 but has to be corrected to 0.9 because the master table has 0.9.
Booking 1 requires a correction so the slave table also has a total of 0.9 (business rule is, corrections only on first booking). so we have
to change the amount from 15.3 to 14.5. I plan my SQL like that:
1. Sum bookings from both tables for each Claim. Compare the two for each individual claim.
2. If the Master sum of the amount shows a difference between the master and slave table
     2.1 select top 1 booking from slave table for the specific claim and increase/decrease by the difference of those two amounts.
Does that make sense?

Answer 1

Hello
It would be really helpful if you could a) format your posting properly using the {noformat}{noformat} tags around your data and b) provide create table/ insert statements.
Anyway, from what you described -
Booking 1 requires a correction so the slave table also has a total of 0.9 (business rule is, corrections only on first booking). so we haveto change the amount from 15.3 to 14.5
You could achieve this with an analytic function and an outer join...WITH Master_Table AS
SELECT 1 Claim, 1 booking, 'D' debit,NULL credit,15.3 masteramount from dual union all
SELECT 1,2,'D',NUll,480.6 from dual union all
SELECT 1,3,NULL,'C',496.8 from dual
Slave_Table AS
( SELECT 1 claim, 1 booking, 'D' debit, null credit, 15.3 slaveamount,14.5 slavecorrection from dual union all
SELECT 1,2,'D',NULL,480.6,480.6 from dual union all
SELECT 1,3,null,'C',496,496 from dual
SELECT
m.claim,
m.booking,
m.debit,
m.credit,
NVL(s.slavecorrection,m.masteramount) amount
FROM
master_table m
LEFT OUTER JOIN
( SELECT
claim,
booking,
slaveamount,
slavecorrection,
ROW_NUMBER() OVER(PARTITION BY claim ORDER BY booking) rn
FROM
slave_table s
) s
ON
( s.claim = m.claim
AND
m.booking = s.booking
AND
s.rn = 1
CLAIM BOOKING D C AMOUNT
1 1 D 14.5
1 2 D 480.6
1 3 C 496.8
HTH
David