What is a correlated sub-query? How can these queries be useful?

Question

Hello
What is a correlated sub-query? How can these queries be useful?
please reply me. i am waiting for your reply.
Thanx

Answer 1

The more seasoned developer will be able to accurately describe this type of query.
A correlated sub-query is a special type of query containing a sub-query. The sub-query contained in the query actually requests values from the outside query, creating a situation similar to a loop. You can find a more detailed description as to how these special types of queries work in this article.