視圖是一個虛擬表（非真實存在），其本質是【根據SQL語句獲取動態的數據集，並為其命名】，用戶使用時只需使用【名稱】即可獲取結果集，並可以將其當作表來使用

一：創建視圖

　　create view viewname as select tname from table1,table2 where condition

MariaDB [test2]> create view student2 as select * from student;
Query OK, 0 rows affected (0.02 sec)

MariaDB [test2]> show tables;
+-----------------+
| Tables_in_test2 |
+-----------------+
| a               |
| b               |
| student         |
| student2        |
+-----------------+
4 rows in
 
 set (0.00 sec)

二：刪除視圖

　　drop view viewname

MariaDB [test2]> drop view student2;
Query OK, 0 rows affected (0.00 sec)

MariaDB [test2]> show tables;
+-----------------+
| Tables_in_test2 |
+-----------------+
| a               |
| b               |
| student         |
+-----------------+
3 rows in set (0.00 sec)

三：修改視圖

　　alter view viewname as select tname from table1,table2 where condition

MariaDB [test2]> alter view student2 as select * from a;
Query OK, 0 rows affected (0.00 sec)

數據庫-mysql視圖