Super Querys

select materia, count(*)/(select count(*) from financieras) as probabilidad from financieras where materia in(select distinct materia from financieras) group by materia;
select materia, count(*)/(select count(*) from financieras) as probabilidad from financieras where materia in(select distinct materia from financieras) and industria in(select distinct industria from arbol) group by industria, materia order by materia, industria;