MySQL VIEWS
The view is a virtual table in MySQL. It has no physical existence. It is created by joining one or more tables.
Syntax:
CREATE [OR REPLACE] VIEW name AS SELECT column_1, column_2, column_3,...... FROM table WHERE view_conditions;
Parameters:
name: It is used to specify the name of the MySQL VIEW to be created.
Example:
CREATE VIEW item AS SELECT id, name FROM items
Output:
Query OK, 0 rows affected <0.10 sec>
Explanation:
A view named “item” is created from the table “items”. Check the created VIEW, using the below query.
SELECT * FROM item;
Output:
ID | NAME |
1 | Electronics |
2 | Sports |
3 | Fashion |
4 | Grocery |
MySQL Update VIEW:
To modify or update the definition of a VIEW in MySQL without dropping, the ALTER VIEW statement is used.
Syntax:
ALTER VIEW name AS SELECT column_1, column_2, column_3,...... FROM table WHERE view_conditions;
Parameters:
name: It is used to specify the name of the MySQL VIEW to be modified.
Example:
ALTER VIEW item AS SELECT id, name, number FROM items
Output:
Query OK, 0 rows affected <0.03 sec>
Explanation:
The view named “item” is updated in the above example. Check the updated VIEW, using the below query.
SELECT * FROM item;
Output:
ID | NAME | NUMBER |
1 | Electronics | 10 |
2 | Sports | 15 |
3 | Fashion | 20 |
4 | Grocery | 30 |
MySQL DROP VIEW
The DROP VIEW statement is used to delete a MySQL VIEW.
Syntax:
DROP VIEW [IF EXISTS] name;
Parameters:
name: It is used to specify the name of the MySQL VIEW to be deleted.
Example:
DROP VIEW item;
Explanation:
The view named “item” will be completely deleted after the execution of the above query.