Example: Decoding IDs
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
Example: Decoding IDs Using NULL
The following query
SELECT DECODE(country_id, 1, 'United States',
2, 'England')
FROM customers;
returns:
- 'United States' if the country_id is 1
- 'England' if country_id is 2
- NULL if country_id isn't in the range 1 to 2
Example: Decoding IDs When ID is Not Equal to 1, 2 or NULL
The following query:
SELECT DECODE(country_id, 1, 'United States',
2, 'England',
NULL, 'France')
FROM customers;
returns:
- 'United States' if the country_id is 1
- 'England' if the country_id is 2
- NULL if the country_id is NULL
- NULL if the country_id is not equal to 1, 2, or NULL