视图

创建视图：
mysql> create or replace view test_view as select a.ename,a.sal,b.deptname from test2 as a ,test1 as b where a.deptno=b.deptno;
Query OK, 0 rows affected (0.04 sec)

mysql>
查看视图:
mysql> show tables;

mysql> select * from test_view;
+--------+---------+----------+
| ename | sal | deptname |
+--------+---------+----------+
| zzx | 2000.00 | tech |
| lisa | 4000.00 | tech |
| bjguan | 5000.00 | hr |
| zzx | 2000.00 | tech |
+--------+---------+----------+
4 rows in set (0.00 sec)

mysql>

mysql> show table status like "test_view"\G
mysql> show create view test_view \G
*************************** 1. row ***************************
View: test_view
Create View: CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `test_view` AS select `a`.`ename` AS `ename`,`a`.`sal` AS `sal`,`b`.`deptname` AS `deptname` from (`test2` `a` join `test1` `b`) where (`a`.`deptno` = `b`.`deptno`)
character_set_client: utf8mb4
collation_connection: utf8mb4_general_ci
1 row in set (0.00 sec)

mysql>
mysql> select * from information_schema.views where table_name="test_view"\G
*************************** 1. row ***************************
TABLE_CATALOG: def
TABLE_SCHEMA: wqh
TABLE_NAME: test_view
VIEW_DEFINITION: select `a`.`ename` AS `ename`,`a`.`sal` AS `sal`,`b`.`deptname` AS `deptname` from `wqh`.`test2` `a` join `wqh`.`test1` `b` where (`a`.`deptno` = `b`.`deptno`)
CHECK_OPTION: NONE
IS_UPDATABLE: YES
DEFINER: root@localhost
SECURITY_TYPE: DEFINER
CHARACTER_SET_CLIENT: utf8mb4
COLLATION_CONNECTION: utf8mb4_general_ci
1 row in set (0.00 sec)

mysql>

删除视图：
mysql> drop view test_view;
Query OK, 0 rows affected (0.00 sec)

mysql>