SQL Subqueries

Types of subqueries:

Scalar subquery

A subquery which returns 1 column and 1 row.

Multiple row subquery

• Multi row, single column subquery – A subquery which returns multiple rows but just a single column.
• Multi row, multi column subqeury – A subquery which returns multiple rows and multiple columns. *

Correlated subquery

A subquery which depends on outer query.