> CREATE TABLE TEST (
> V1 DECIMAL(18,4),
> V2 DECIMAL(18,4),
> V3 DECIMAL(18,4)
> );
>
> INSERT INTO TEST (V1, V2, V3) VALUES (10000000, 1, 1);
>
> SELECT V1*V2*V3 FROM TEST
>
> The select statement generate an unespected INTEGER OVERFLOW

Resulting type of your multiplication is DECIMAL(18,12)
(because you use exact numerics), and as you can see,
the value 10000000 does not fit in.

Ivan