SQL ALTER VIEW view modify usage

ALTER TABLE allows you to modify the structure of an existing table. For example, you can add or delete columns, create or eliminate indexes, change the type of existing columns, or rename columns or the table itself. You can also change the annotation of the table and the type of the table, but you can also modify the view. Take a look at the example below. ALTER VIEW syntax alter [algorithm = {UNDEFINED | MERGE | TempTable}] VIEW view_name [(column_list)] as select_statement [with [cascaded | Local CHECK OPTION] This statement is used to change the definition of an existing view. Its syntax is similar to create view like MySQL tutorial > mysql> create TABLE Employee (-> ID int,-> first_name VARCHAR (),-> last_name VARCHAR,-> start_date date,-> end_date date,-> salary FLOAT (8,2),-> City VARCHAR (a),-> Descripti On VARCHAR ()->); Query OK, 0 rows affected (0.02 sec) mysql> mysql> mysql> insert INTO Employee (Id,first_name, last_name, Start_da Te, end_date, salary, city, Description)-> values (1, ' Jason ', ' Martin ', ' 19960725 ', ' 20060725 ', 1234.56, ' Toronto ', ' P Rogrammer '); Query OK, 1 row Affected (0.00 sec) mysql> mysql> insert INTO Employee (Id,first_name, last_name, Start_date, End_dat E, salary, city, Description)-> values (2, ' Alison ', ' Mathews ', ' 19760321 ', ' 19860221 ', 6661.78, ' Vancouver ', ' Tester '); Query OK, 1 row Affected (0.00 sec) mysql> mysql> insert INTO Employee (Id,first_name, last_name, Start_date, End_dat E, salary, city, Description)-> values (3, ' James ', ' Smith ', ' 19781212 ', ' 19900315 ', 6544.78, ' Vancouver ', ' Tester '); Query OK, 1 row Affected (0.00 sec) mysql> mysql> insert INTO Employee (Id,first_name, last_name, Start_date, End_dat E, salary, city, Description)-> values (4, ' Celia ', ' Rice ', ' 19821024 ', ' 19990421 ', 2344.78, ' Vancouver ', ' Manager '); Query OK, 1 row Affected (0.00 sec) mysql> mysql> insert INTO Employee (Id,first_name, last_name, Start_date, End_dat E, salary, city, Description)-> values (5, ' Robert ', ' black ', ' 19840115 ', ' 19980808 ', 2334.78, ' Vancouver ', ' Tester '); Query OK, 1 row Affected (0.00 sec) mysql> mysql> insert INTO Employee (Id,first_name, last_name, Start_date, End_dat E, salary, city, Description)-> values (6, ' Linda ', ' Green ', ' 19870730 ', ' 19960104 ', 4322.78, ' New York ', ' Tester'); Query OK, 1 row affected (0.02 sec) mysql> mysql> insert INTO Employee (Id,first_name, last_name, Start_date, End_dat E, salary, city, Description)-> values (7, ' David ', ' Larry ', ' 19901231 ', ' 19980212 ', 7897.78, ' New York ', ' Manager '); Query OK, 1 row Affected (0.00 sec) mysql> mysql> insert INTO Employee (Id,first_name, last_name, Start_date, End_dat E, salary, city, Description)-> values (8, ' James ', ' Cat ', ' 19960917 ', ' 20020415 ', 1232.78, ' Vancouver ', ' Tester '); Query OK, 1 row Affected (0.00 sec) mysql> mysql> select * from Employee; +------+------------+-----------+------------+------------+---------+-----------+-------------+ | ID | first_name | last_name | start_date | end_date | Salary | City | Description | +------+------------+-----------+------------+------------+---------+-----------+-------------+ | 1 | Jason | Martin | 1996-07-25 | 2006-07-25 | 1234.56 | Toronto | Programmer | | 2 | Alison | Mathews | 1976-03-21 | 1986-02-21 | 6661.78 | Vancouver | Tester | | 3 | James | Smith | 1978-12-12 | 1990-03-15 | 6544.78 | Vancouver | Tester | | 4 | Celia | Rice | 1982-10-24 | 1999-04-21 | 2344.78 | Vancouver | Manager | | 5 | Robert | Black | 1984-01-15 | 1998-08-08 | 2334.78 | Vancouver | Tester | | 6 | Linda | Green | 1987-07-30 | 1996-01-04 | 4322.78 | New York | Tester | | 7 | David | Larry | 1990-12-31 | 1998-02-12 | 7897.78 | New York | Manager | | 8 | James | Cat | 1996-09-17 | 2002-04-15 | 1232.78 | Vancouver | Tester | +------+------------+-----------+------------+------------+---------+-----------+-------------+ 8 rows in Set (0.00 SEC) mysql> mysql> mysql> mysql> Create VIEW myview (id,first_name,city)-> as SELECT ID, first_name, city from employee; Query OK, 0 rows Affected (0.00 sec) mysql> mysql> select * from MyView; +------+------------+-----------+ | ID | first_name | City | +------+------------+-----------+ | 1 | Jason | Toronto | | 2 | Alison | Vancouver | | 3 | James | Vancouver | | 4 | Celia | VancOuver | | 5 | Robert | Vancouver | | 6 | Linda | New York | | 7 | David | New York | | 8 | James | Vancouver | +------+------------+-----------+ 8 rows in Set (0.00 sec) mysql> mysql> mysql> ALTER VIEW myview (Id,first_name, City)-> as SELECT ID, Upper (first_name), city from employee; Query OK, 0 rows Affected (0.00 sec) mysql> mysql> select * from MyView; +------+------------+-----------+ | ID | first_name | City | +------+------------+-----------+ | 1 | JASON | Toronto | | 2 | ALISON | Vancouver | | 3 | JAMES | Vancouver | | 4 | CELIA | Vancouver | | 5 | ROBERT | Vancouver | | 6 | LINDA | New York | | 7 | DAVID | New York | | 8 | JAMES | Vancouver | +------+------------+-----------+ 8 rows in Set (0.02 sec) mysql> mysql> drop view myview; Query OK, 0 rows Affected (0.00 sec) mysql> mysql> mysql> mysql> mysql> mysql> drop table Employee; Query OK, 0 rows Affected (0.00 sec) mysql>