A subquery, also known as an inner query or nested query, is a query nested within another SQL query. Subqueries are often used to retrieve data that will be used in the main query to further filter, ...

For example, you can use a subquery to find the average salary of employees in a department, ... A Sub query is embedded within another SQL query.

Using a Pass-Through Query in a Subquery The next example shows how to use a subquery that contains a Pass-Through query. A subquery is a nested query and is usually part of a WHERE or HAVING clause.

The result of an EXISTS condition is true if the subquery resolves to at least one row. The result of a NOT EXISTS condition is true if the subquery evaluates to zero rows. For example, the following ...