Different types of a subquery

Question

Hi!!

Can someone tell me what are the different types of subquery?

Answer 1

There are two types of subquery namely, Correlated and Non-Correlated.

Correlated subquery: These are queries which select the data from a table referenced in the outer query. It is not considered as an independent query as it refers to another table and refers the column in a table.

Non-Correlated subquery: This query is an independent query where the output of subquery is substituted in the main query.