Great! The query we just ran is just one kind of subquery, what we refer to as a non-correlated subquery. A non-correlated subquery is a subquery that can be run independently of the outer query and as we saw, can be used to complete a multi-step transformation.
Let’s try one more non-correlated subquery. Perhaps we’d like to look at a selection of flights whose origin airport is in Los Angeles. The name of an airport’s city is stored in the
city field of the airports table.
SELECT * FROM flights WHERE origin in ( SELECT code FROM airports WHERE city = 'LOS ANGELES');
Using the same pattern, find flight information about flights where the Federal Aviation Administration region (
faa_region) is the Southern region (