subtracting two diff columns

Hi

I am confused how to do this.

I have two tables and each table has an "Amount" colum.

I need to sum up all the rows for column "Amount" in table A and sum up all the rows for column "Amount" in table B

and then subtract those two colums.

Here is what I am doing:

Code:

`select tableA.city, sum(tableA.amount) - sum(tableB.amount)`

from tableB,tableA

where

tableB.city='Hyderabad' and

tableB.city=tableA.city

group by tableB.city

Say: tableA Has the following data for column "Amount" and city=Hyderabad:

AND tableB Has the following data for column "Amount" and city=Hyderabad:

Now, my above query should do the following:

Sum all amounts for tableA, which comes to 126

Sum all amounts for tableB, which comes to 11

So 126 - 11 = **115**

But I get the result **219**

Any idea wots going on and how to fix it?

Thanx