-- Database schema
| storm : Storm_ID [ INT ] primary_key , Name [ TEXT ] , Dates_active [ TEXT ] , Max_speed [ INT ] , Damage_millions_USD [ INT ] , Number_Deaths [ INT ] | region : Region_id [ INT ] primary_key , Region_code [ TEXT ] , Region_name [ TEXT ] | affected_region : Region_id [ INT ] primary_key affected_region.Region_id = region.Region_id , Storm_ID [ INT ] affected_region.Storm_ID = storm.Storm_ID , Number_city_affected [ INT ] |
-- -- What are the names of regions that were not affected?

SELECT region_name FROM region WHERE region_id NOT IN (SELECT region_id FROM affected_region);