SQL VIEW

What is view?

In SQL, a view is a virtual table that does not physically store data but retrieves data from one or more existing tables in the database.

• A view can either have specific rows based on certain condition or all the rows of a table.
• A view can be created using the CREATE VIEW statement. We can create a view from a single table or multiple tables.

1.creating view with single table :

Syntax:

CREATE VIEW view_name AS

SELECT column1, column2…..

FROM table_name

WHERE condition;

Example:

example of view with single table

2.creating view with multiple tables:

Syntax:

CREATE VIEW view_name AS

SELECT table1.NAME, table1.ADDRESS, table2.MARKS

FROM table1, table2

WHERE table1.common_col=table2.common_col;

Example :

example of view on multiple tables

note that we also can delete the view if not required by using following query:

DROP VIEW view_name;

The benefits of using views include:

• Simplifying complex queries: views can be used to complex queries and make them easier to read and use.
• Hiding sensitive information: views can be used to restrict access to sensitive information by selecting only the necessary columns and filtering out unwanted data.
• Reusing SELECT statements: views can be used to save frequently used SELECT statements as reusable objects.
• Improving performance: views can improve performance by SELECT statements or aggregating data.

Overall, views are a useful tool in SQL for organizing and simplifying complex queries, securing sensitive information, and improving performance.

Thank you!