How to Use Subqueries in SQL
In this article I am going to explain how to use Subqueries in SQL.
Introduction
In this article I am going to explain how to use Subqueries in SQL. A select statement known as subquery if it is codded within another SQL statement. Subquery can return a single value or a result set. This result set may contain a single column or more than one column.
There are four way to create subquery in a SELECT statement.
- In WHERE Clause
- In HAVING Clause
- In FROM Clause
- In SELECT Clause
Example
|
select * from mcninvoices
where invoicetotal >
( select avg(invoicetotal) from invoices )
|
Output
