The following query:
SELECT DECODE(country_id, 1, 'United States', 2, 'England', 3, 'France', 'United States') FROM customers;
returns:
- 'United States' if the country_id is 1
- 'England' if the country_id is 2
- 'France' if the country_id is 3
- 'United States' if the country_id is not equal to 1, 2, or 3