An SQL view is a virtual table or a logical table in a database management system (DBMS), that is defined or created by a SELECT statement or a SELECT query. An SQL view is used to represent or to display a specific subset or a specific view of the data in a database, based on the SELECT statement or the SELECT query that defines the view. An SQL view does not store any data itself, but it retrieves or displays the data from the underlying tables or the base tables in the database, based on the SELECT statement or the SELECT query that defines the view.

An SQL view can be created using the CREATE VIEW statement, and it can be queried or accessed using the SELECT statement, just like a regular table. Here is an example of how to create and query an SQL view in a database:

-- Create an SQL view called 'employees_view' that displays the 'name' and 'salary' columns from the 'employees' table
CREATE VIEW employees_view AS
SELECT name, salary FROM employees;

-- Select all rows from the 'employees_view' view
SELECT * FROM employees_view;

-- Select only the rows from the 'employees_view' view where the 'salary' is greater than 10000
SELECT * FROM employees_view WHERE salary > 10000;

The above SQL code will create an SQL view called ’employees_view’ that displays the ‘name’ and ‘salary’ columns from the ’employees’ table, based on the SELECT statement or the SELECT query that defines the view. The SQL code will then select all rows from the ’employees_view’ view, using the SELECT statement. Finally, the SQL code will select only the rows from the ’employees_view’ view where the ‘salary’ is greater than 10000, using the SELECT statement and a WHERE clause.

SQL views are a useful and convenient way to represent or to display a specific subset or a specific view of the data in a database, based on a SELECT statement or a SELECT query. SQL views are created using the CREATE VIEW statement, and they can be queried or accessed using the SELECT statement, just like a regular table. SQL views do not store any data themselves, but they retrieve or display the data from the underlying tables or the base tables in the database, based on the SELECT statement or the SELECT query that defines the view.