mysql常用表管理语句
【摘要】 笔记。
#查看库下面有多少张表.
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| boy |
| boy2 |
| boy3 |
| course |
| pj |
| sc |
| sc2 |
| stage |
| student |
+----------------+
9 rows in set (0.00 sec)
#删除视图
mysql> drop view pj;
Query OK, 0 rows affected (0.00 sec)
#删除表
mysql> drop tables sc;
Query OK, 0 rows affected (0.02 sec)
#查看表结构信息
mysql> desc boy;
+--------+--------------+------+-----+------------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------+--------------+------+-----+------------+-------+
| hid | int(11) | NO | | NULL | |
| bname | varchar(100) | NO | | NULL | |
| birth | date | NO | | 0000-00-00 | |
| weight | smallint(6) | YES | | NULL | |
+--------+--------------+------+-----+------------+-------+
4 rows in set (0.00 sec)
#查看建表的过程、语句.
mysql> show create table boy;
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| boy | CREATE TABLE `boy` (
`hid` int(11) NOT NULL,
`bname` varchar(100) NOT NULL,
`birth` date NOT NULL DEFAULT '0000-00-00',
`weight` smallint(6) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
#查看视图建表过程(table/view都可以)
mysql> show create table stage;
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+
| View | Create View | character_set_client | collation_connection |
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+
| stage | CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `stage` AS select `student`.`SNAME` AS `sname`,`student`.`AGE` AS `age` from `student` | utf8 | utf8_general_ci |
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+
1 row in set (0.00 sec)
mysql> show create view stage;
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+
| View | Create View | character_set_client | collation_connection |
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+
| stage | CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `stage` AS select `student`.`SNAME` AS `sname`,`student`.`AGE` AS `age` from `student` | utf8 | utf8_general_ci |
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+
1 row in set (0.00 sec)
#查看表的信息和过程(所有表).
mysql> show table status \G;
*************************** 1. row ***************************
Name: boy
Engine: InnoDB
Version: 10
Row_format: Compact
Rows: 4
Avg_row_length: 4096
Data_length: 16384
Max_data_length: 0
Index_length: 0
Data_free: 0
Auto_increment: NULL
Create_time: 2019-01-29 00:33:46
Update_time: NULL
Check_time: NULL
Collation: utf8_general_ci
Checksum: NULL
Create_options:
Comment:
#单独的查看某张表的状态、信息.
mysql> show table status where name="student" \G;
*************************** 1. row ***************************
Name: student
Engine: InnoDB
Version: 10
Row_format: Compact
Rows: 4
Avg_row_length: 4096
Data_length: 16384
Max_data_length: 0
Index_length: 0
Data_free: 0
Auto_increment: NULL
Create_time: 2018-09-21 00:55:30
Update_time: NULL
Check_time: NULL
Collation: utf8_general_ci
Checksum: NULL
Create_options:
Comment:
1 row in set (0.00 sec)
ERROR:
No query specified
清空表数据truncate和delete的区别?
使用delete对表中的数据进行操作:
#创建t2表
mysql> create table t2 ( id int primary key auto_increment );
Query OK, 0 rows affected (0.02 sec)
mysql> select * from t2;
Empty set (0.00 sec)
#插入两行数据.
mysql> insert into t2 values (null);
Query OK, 1 row affected (0.01 sec)
mysql> insert into t2 values (null);
Query OK, 1 row affected (0.01 sec)
mysql> select * from t2;
+----+
| id |
+----+
| 1 |
| 2 |
+----+
2 rows in set (0.00 sec)
#delete其中的一条数据.
mysql> delete from t2 where id="2";
Query OK, 1 row affected (0.00 sec)
#再次插入数据.
mysql> insert into t2 values (null);
Query OK, 1 row affected (0.01 sec)
#发现插入的id从3开始,继续原数据的id增长.
mysql> select * from t2;
+----+
| id |
+----+
| 1 |
| 3 |
+----+
2 rows in set (0.00 sec)
使用truncate对表中的数据进行操作:
#表中的数据清空.
mysql> truncate table t2;
Query OK, 0 rows affected (0.02 sec)
#插入数据
mysql> insert into t2 values (null);
Query OK, 1 row affected (0.01 sec)
#发现表的id从1开始.
mysql> select * from t2;
+----+
| id |
+----+
| 1 |
+----+
1 row in set (0.00 sec)
注意:truncate操作其实相当与对表进行了drop tables---create table操作.
----------------
本文转自青衫解衣博客51CTO博客
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原文链接:http://blog.51cto.com/215687833/2352593
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