Database: city_record
Question: Which cities have lower temperature in March than in Dec and have never served as host cities?
SQL: select t1.city from city as t1 join temperature as t2 on t1.city_id  =  t2.city_id where t2.mar  <  t2.dec except select t3.city from city as t3 join hosting_city as t4 on t3.city_id  =  t4.host_city