Oracle Discoverer Problem - Find Difference of amounts

Question

Hi ,
I need your help / suggestions on how to achieve the following in Oracle Discoverer.
I am having 2 custom tables, using a UNION in the Discoverer query, showing the report as
1. sum of amount column from Table A - always 1 row.
2. sum of amount columns from Table B , but group by a criteria and will be many rows depending on the parameters.
I need to show the difference between the amounts as explained below.
Eg.
1st row: Trial Balance for Jun'06 - 100$
2nd row: For schedule 1 - 10$
3rd row: For Schedule 2 - 30$
4th row: For Schedule 3 - 40$
5th Row: For Schedule 4 - 10$
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Difference - 10$
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How do I achieve this in Discoverer. It seems i can do a minus only between two adjacent cells in a single row.
I want the difference between the 1st row and the (sum of all the rest of the rows).
Please help me to achieve this in Oracle Discoverer.
Version: Oracle Discoverer Desktop 10.1.2.48 on Oracle 10G database.
Any suggestions are highly appreciated.
Thanks & Regards,
Kiran Kesari

Answer 1

as you said you are using UNION to retrieve data from two different tables, you can simply convert amount to negative amount in query like
select sum(amount),'desc' <column-name> from table a
union
select -sum(amount),abc from table b group by abc
after that you need to create grand total on amount column and you will get what you want. only problem is that amount from second table will display as negative. but you can change number format for negative value so probably it will help you..