CREATE TABLE city (city_id VARCHAR)
CREATE TABLE hosting_city (host_city VARCHAR)

What are the GDP and population of the city that already served as a host more than once?
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
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