Question

what is a subquery ?
1. a subquery is a select-from-where expression that is nested within another query
2. a subquery is any query that is nested within another query
3. a subquery is a relation that is externally specified which can be used to handle data in queries
4. a subquery is a condition that excludes all the invalid tuples from the database

Answer 1

A subquery is

2. a) query that is nested within another query

Answer 2

Answer:

Among the 4 options available, the answer to the question mentioned above is that a subquery is a select-from-where expression that is nested within another query.

It has been put to use in many cases. Notably, it is used to create tests for set comparisons or set memberships. These are nested queries that provide an answer to the other enclosed queries.

Explanation: