Table: nfl_europe_teams
Columns: team
stadium
capacity
opened
city

Question: What is the latest opened year of the team in Glasgow, Scotland?
SQL: SELECT MAX("opened") FROM nfl_europe_teams WHERE "city" = 'glasgow, scotland'

Question: What is the average opened year of Mini Estadi stadium in Barcelona, Spain?
SQL: SELECT AVG("opened") FROM nfl_europe_teams WHERE "city" = 'barcelona, spain' AND "stadium" = 'mini estadi'