Sql problems in large databases (Help)????
I have a large database, Where I have two tables claims and invoices. In invoice table when I run the query
select sum(amount) from invoices.
Gives me value of 207859507
However when I join two tables and group then by one variable such as mileage in claim table
SELECT c.mileage, SUM(i.amount) AS amount
FROM claims c
INNER JOIN invoices i
ON i.ID = c.ID AND i.accident_date = c.accident_date
GROUP BY mileage
it gives me a greater value i.e. 214110863...
But conceptually the join must have smaller value then the other query