CREATE TABLE competition (country VARCHAR, competition_type VARCHAR)

which countries did participated in both Friendly and Tournament type competitions.
SELECT country FROM competition WHERE competition_type = 'Friendly' INTERSECT SELECT country FROM competition WHERE competition_type = 'Tournament'
SELECT "country" FROM "competition" WHERE "competition_type" = 'Friendly' INTERSECT SELECT "country" FROM "competition" WHERE "competition_type" = 'Tournament'