mysql> create view v1 as select * from t2;python
Query OK, 0 rows affected (0.02 sec)mysql
刪除主表的時候 那麼視圖表就不起做用了sql
mysql> drop table t2;函數
Query OK, 0 rows affected (0.02 sec)ui
mysql> select * from v1;spa
ERROR 1356 (HY000): View 'python.v1' references invalid table(s) or column(s) or function(s) or definer/invoker of view命令行
mysql> show tables;字符串
刪除視圖表io
mysql> drop view v1;table
Query OK, 0 rows affected (0.00 sec)
mysql> select ucase('name') from stu; -----這個含義是讓字符串name變成大寫而不是讓name字段裏面全部的值變成大寫
+---------------+
| ucase('name') |
+---------------+
| NAME |
| NAME |
| NAME |
mysql> select ucase(name) from stu; -----這個含義是 讓name字段裏面的全部值變成大寫
+------------------+
| ucase(name) |
+------------------+
| |
| 22WEW |
| 666 |
| AA |
| AABB |
| CAO |
| EEE |
mysql> select length('dsjfkdsfiefuie');
若是不起別名的話那麼現實出來的字段名就是你查詢出來的名字
+--------------------------+
| length('dsjfkdsfiefuie') |
+--------------------------+
| 14 |
+--------------------------+
1 row in set (0.00 sec)
若是你起了別名,那麼現實出來的名字就是你的別名
mysql> select length('dsfdsfdsfds') as len;
+-----+
| len |
+-----+
| 11 |
+-----+
1 row in set (0.00 sec)
給表名起一個別名 使用as
mysql> select a.name,c.childname from type as a,typechild as c where a.id = c.pid;
不使用 as
mysql> select a.name,c.childname from type a,typechild c where a.id = c.pid;
mysql> prepare stmt from 'select * from stu where id > ?'
Query OK, 0 rows affected (0.01 sec)
Statement prepared
mysql> set @id = 5;
Query OK, 0 rows affected (0.00 sec)
mysql> execute stmt using @id;
+----+------------------+-----+-----+----------+
| id | name | age | sex | classid |
+----+------------------+-----+-----+----------+
| 7 | uu03 | 26 | m | lamp103 |
| 8 | uu04 | 27 | w | lamp105 |
mysql> create procedure intos(num int)
-> begin
-> set @i = 0;
-> while @i <= num do
-> insert into t3 values (2,'we232');
-> set @i = @i+1;
-> end while;
-> end#
Query OK, 0 rows affected (0.00 sec)
mysql> call intos(10)#
Query OK, 0 rows affected (0.04 sec)
建立觸發器 tg5
mysql> create trigger tg5 after insert on t4 for each row
-> begin
-> update t5 set name='bbbb' where id = 2;
-> end#
Query OK, 0 rows affected (0.02 sec)
mysql> select * from t5#
+----+--------+
| id | name |
+----+--------+
| 1 | aaaa |
| 2 | ???? |
| 3 | 我很你 |
+----+--------+
3 rows in set (0.00 sec)
往t4表中插入數據的時候要改變t5表的信息
mysql> insert into t4(id,name) values (9,'wew23232')#
Query OK, 1 row affected (0.02 sec)
mysql> select * from t5#
+----+--------+
| id | name |
+----+--------+
| 1 | aaaa |
| 2 | bbbb |
| 3 | 我很你 |
+----+--------+
3 rows in set (0.00 sec)