Table schema:
CREATE TABLE hosting_city (host_city VARCHAR); CREATE TABLE city (city_id VARCHAR)

Question: What are the GDP and population of the city that already served as a host more than once?
SQL: SELECT t1.gdp, t1.Regional_Population FROM city AS T1 JOIN hosting_city AS T2 ON T1.city_id = T2.host_city GROUP BY t2.Host_City HAVING COUNT(*) > 1