CREATE TABLE companies (id NUMBER, name CLOB, headquarters CLOB, industry CLOB, sales_billion NUMBER, profits_billion NUMBER, assets_billion NUMBER, market_value_billion CLOB)
CREATE TABLE buildings (id NUMBER, name CLOB, city CLOB, height NUMBER, stories NUMBER, status CLOB)
CREATE TABLE office_locations (building_id NUMBER, company_id NUMBER, move_in_year NUMBER)

Show the headquarters shared by more than two companies.
SELECT headquarters FROM companies GROUP BY headquarters HAVING COUNT(*) > 2
SELECT "headquarters" FROM "companies" GROUP BY "headquarters" HAVING COUNT(*) > 2