Código SQL [-] select t1.campo1, t1.campo2,...., (t1.campoX * t2.campoX) as Multiplicacion from tabla1 t1 inner join tabla2 t2 on t2.CampoUnion = t1.CampoUnion where .......
select t1.campo1, t1.campo2,...., (t1.campoX * t2.campoX) as Multiplicacion from tabla1 t1 inner join tabla2 t2 on t2.CampoUnion = t1.CampoUnion where .......