Question

Which subquery cannot be executed by itself as a separate statement?

(a) Correlated

(b) Uncorrelated

(c) EXISTS

(d) NOT EXISTS

This question was addressed to me at a job interview.

I'd like to ask this question from Performing Multiple topic in division Using SQL to Manage Data of MySQL

Answer 1

Correct choice is (a) Correlated

The best I can explain: An uncorrelated subquery contains references to the values from the outer query. So, it is dependent on it. Therefore, a correlated subquery cannot be executed by itself as a separate statement.