SQL Views

A SQL View is a virtual table, which is based on SQL SELECT query. Essentially a view is very close to a real database table (it has columns and rows just like a regular table), except for the fact that the real tables store data, while the views don't. The view's data is generated dynamically when the view is referenced. A view references one or more existing database tables or other views. In effect every view is a filter of the table data referenced in it and this filter can restrict both the columns and the rows of the referenced tables.

Here is an example of how to create a SQL view using already familiar Product and Manufacturer SQL tables:

CREATE VIEW vwAveragePrice AS SELECT Manufacturer, ManufacturerWebsite, ManufacturerEmail, AVG(Price) AS AvgPrice FROM Manufacturer JOIN Product ON Manufacturer.ManufacturerID = Product.ManufacturerID GROUP BY Manufacturer, ManufacturerWebsite, ManufacturerEmail

A view can be referenced and used from another view, from a SQL query, and from stored procedure. You reference a view as you would reference any real SQL database table:

SELECT * FROM vwAveragePrice