Quantos países falam inglês e holandês?
CREATE TABLE country (Name VARCHAR, Code VARCHAR); CREATE TABLE countrylanguage (CountryCode VARCHAR, Language VARCHAR)
SELECT COUNT(*) FROM (SELECT T1.Name FROM country AS T1 JOIN countrylanguage AS T2 ON T1.Code = T2.CountryCode WHERE T2.Language = "English" INTERSECT SELECT T1.Name FROM country AS T1 JOIN countrylanguage AS T2 ON T1.Code = T2.CountryCode WHERE T2.Language = "Dutch")