SQL Indexes

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 AvgPriceFROM Manufacturer JOIN ProductON Manufacturer.ManufacturerID = Product.ManufacturerIDGROUP 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