What is the concept of VIEW in MySQL?

In MySQL, a "view" is a virtual table that is based on the result of a SELECT query. It behaves like a regular table in many ways, but it doesn't store any data on its own. Instead, it's a saved query that you can reference and use like a table in your database.

Views provide several benefits:

1. Data Abstraction: 

Views allow you to abstract complex queries or data transformations into a simpler, more user-friendly structure. Users can interact with the view without needing to understand the underlying SQL logic.

2. Security: 

Views can help enforce security by allowing you to control what data is accessible to different users. You can restrict access to specific columns or rows in the view based on user permissions.

3. Simplification:

 Views can simplify data access by presenting a subset of columns or rows from one or more tables. This is particularly useful when dealing with large and complex databases.

4. Data Integrity: 

Views can be used to enforce data integrity rules. For instance, you can create a view that shows only rows where a certain condition is met, ensuring that only valid data is visible.

5. Performance: 

In some cases, views can improve performance by precalculating complex joins, aggregations, or calculations. This can reduce the workload on queries that use the view.

Creating a view in MySQL involves defining the SELECT query that will be used as the basis for the view. Here's a   basic example:

 CREATE VIEW  employee_view   AS SELECT   employee_id ,  first_name ,  last_name  FROM   employees  WHERE  department = 'Sales';

In this example, a view named employee_view is created based on the employees table. It includes only the columns employee_id, first_name, and last_name for employees who belong to the 'Sales' department.

To use a view, you can treat it like a regular table in your SQL queries: 

SELECT * FROM  employee_view;

This query will retrieve data from the employee_view  view as if it were an actual table.