Table schema:
CREATE TABLE city (city VARCHAR, city_id VARCHAR); CREATE TABLE hosting_city (host_city VARCHAR); CREATE TABLE temperature (city_id VARCHAR, Feb INTEGER, Jun VARCHAR)

Question: Give me a list of cities whose temperature in Feb is higher than that in Jun or cities that were once host cities?
SQL: SELECT T1.city FROM city AS T1 JOIN temperature AS T2 ON T1.city_id = T2.city_id WHERE T2.Feb > T2.Jun UNION SELECT T3.city FROM city AS T3 JOIN hosting_city AS T4 ON T3.city_id = T4.host_city