SQL case statement in Teradata - sql

Question

I'm trying to write a simple IF/ELSE statement in Teradata. As far as I understand you have to use a CASE. What I want to do is write a statement that will check if a column IS NOT NULL and display something. ELSE if it IS NULL, display something else.
Every example I found simply replaces a single value with a hard coded string or int. I'm looking for something more along the lines of this which uses the THEN statement to make another SELECT:
SELECT CARS.VIN_NUM, CARS.DRIVER_NAMES
CASE
WHEN CARS.FUEL IS NOT NULL THEN SELECT CARS.DESTINATIONS
WHEN CARS.FUEL IS NULL THEN SELECT CARS.GAS_STATIONS
END
FROM AUTOMOBILES CARS
WHERE CARS.VIN_NUM IN
('345353',
'354632',
'535231')
ORDER BY CARS.VIN_NUM
The end result should be a table displaying the VIN_NUM, DRIVER_NAMES, DESTINATIONS OR GAS_STATIONS based on the CASE. Is something like this possible or am I going about it the wrong way?

Answer 1

If DESTINATIONS and GAS_STATIONS are columns in the table AUTOMOBILES (aliased CARS) then the following should work:
SELECT CARS.VIN_NUM,
CARS.DRIVER_NAMES,
CASE
WHEN CARS.FUEL IS NOT NULL THEN CARS.DESTINATIONS
ELSE CARS.GAS_STATIONS
END
FROM AUTOMOBILES CARS
WHERE CARS.VIN_NUM IN
('345353',
'354632',
'535231')
ORDER BY CARS.VIN_NUM;