Need help in select statement from two tables

Databases
1

Hi,
Good day!
I have a problem in my select query statement to get the value of reject from op_reject table and spv_reject table in one row
here is my query:

SELECT o.compound_type, SUM(o.reject) AS op_reject, s.compound_type, SUM(s.reject) AS spv_reject
FROM op_reject AS o ,spv_reject AS s
WHERE o.compound_type = 'P28' AND s.compound_type = 'P28'
AND o.process_id = '2' AND s.process_id = '2'
AND o.reject_date = '2013-09-30' AND s.reject_date = '2013-09-30'
GROUP BY  o.compound_type, o.process_id;

this code has an output:
P28|6.00|P28|6.00
but it should only be:
P28|3.00|P28|3.00
because the sum of rejects are only 3.00
I attached my database for your reference.
Any help is highly appreciated.
Thank you so much.

2

In your query you didn’t specify any join condition, so all rows from the two tables that meet the select criteria will be cross-joined to each other. In this specific case, looking at the data in your database, you have two rows in each table that are selected, with 1 and 2 as reject values. The final join result is:


op_reject   spv_reject
1                1
2                2
1                2
2                1

And the sum of both is 6 and 6.