When determining which airports are >2000 elevation, they used:
WHERE elevation > 2000;
1) What is the significance of specifying the "code" column? This leads to my next question...
When determining which flights originated from airports>2000, they use:
WHERE origin in (
WHERE elevation > 2000);
The 'origin' from flights dictate a specific airport name while 'code' from airports dictate a specific airport. How are they connected/logic behind it?