Calculations in SQL

We're using RDBMS 6.0.36.7.1, on an HP-UX (not that I feel the platform is especially relevant).
I've got two tables: table one has a number field called connects, table two has a number field called irequests. The tables don't have fields of the same name.

The tables are created in such a way that the total 'connects' in table1 should equal to the total 'irequests' in table2.

I want to check that this is so while the tables are being updated. The speed of Oracle is such (!) that if I do this in two separate sql statements, they won't be simultaneous. So I tried the statement
select sum(connects),sum(irequests) from table1,table2

and got utterly different results: one result was 8 digits instead of 4, the other was 6 digits instead of 4.

The only thought that crossed my mind was that SQL had done a join of some kind: but why?

Mavis

-- 
Mavis Hearnden
Computer Centre
Loughborough University,
Leicestershire