What is a noncorrelated subquery?

Which type of subquery can be executed on its own?

Which part of a query is evaluated first, the query or the subquery?

What are correlated subqueries?

What does the EXISTS predicate do?

What are considered universal qualifiers?

Is correlation necessary when we use EXISTS? Why?

Explain how the "for all" type SQL query involves a double-nested correlated subquery using the NOT EXISTS predicate.