programa 2

select campo1, count(*)/(select count(*) from tabla) as probabilidad from tabla where campo1 in (select distinct campo1 from tabla) group by campo1;

select campo1, campo2, count(*)/(select count(*) from tabla) as Probabilidad from tabla where campo1 in (select distinct campo1 from tabla) and campo2 in (select distinct campo2 from tabla)group by campo2, campo1 order by campo1, campo2;