SQL Nested Queries

A SQL nested query is a SELECT query that is nested inside a SELECT, UPDATE, INSERT, or DELETE SQL query. Here is a simple example of SQL nested query:

SELECT Model FROM Product WHERE ManufacturerID IN (SELECT ManufacturerID FROM Manufacturer WHERE Manufacturer = 'Dell')

The nested query above will select all models from the Product table manufactured by Dell:

Inspiron B120
Inspiron B130
Inspiron E1705

You can have more than one level of nesting in one single query.