Table: real_madrid_football
Columns: club
league
sport
venue
established
capacity

Question: What is the venue established after 1948?
SQL: SELECT "venue" FROM real_madrid_football WHERE "established" > 1948

Question: What is the league established before 1930 with the rayo vallecano club?
SQL: SELECT "league" FROM real_madrid_football WHERE "established" < 1930 AND "club" = 'rayo vallecano'

Question: What sport is the rayo vallecano club in?
SQL: SELECT "sport" FROM real_madrid_football WHERE "club" = 'rayo vallecano'

Question: What sport is the cb estudiantes club in?
SQL: SELECT "sport" FROM real_madrid_football WHERE "club" = 'cb estudiantes'