I have this table 
The teams are related to another table called teams. Containing: name (primary key), stadium, city and foundation. 
.
With these two tables I would like to draw a classification of the teams with their points. Example: Real Madrid 20, Athletic 19.
Finding out with local goals and visitors. Example if crazy goals > visiting goals; Local Team has 3 points.
You can try this, to add the points that each local team gets as a visitor:
SELECT
@curRank := @curRank + 1 AS rank,
Equipo,sum(puntos) as puntos FROM (
select Equipo_local as Equipo,
sum(CASE WHEN Goles_local>Goles_visitante then 3 WHEN Goles_local=Goles_visitante then 1 else 0 END) as puntos
from equipo
Group by Equipo_local
UNION
SELECT Equipo_visitante as Equipo,
sum(CASE WHEN Goles_local<Goles_visitante then 3 WHEN Goles_local=Goles_visitante then 1 else 0 END) as puntos
from equipo
Group by Equipo_visitante) t,(SELECT @curRank := 0) r
group by t.Equipo