您当前的位置:首页 > 计算机 > 软件应用 > 数据库 > MySQL

MySQL基本简单操作02

时间:12-20来源:作者:点击数:
MySQL基本简单操作

先进入Mysql容器。

[root@promote ~]# docker exec -it mysql /bin/bash
root@30d60b852cf5:/# mysql -uroot -p000000
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.11 MySQL Community Server - GPL

Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

新建一个数据库。

mysql> create database gubeiqing;
Query OK, 1 row affected (0.02 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| gubeiqing          |
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.01 sec)

进入数据库,新建数据表。

mysql> use gubeiqing;
Database changed
mysql> show tables;
Empty set (0.00 sec)

mysql> create table gubeiqing_table(name varchar(20) not null , age varchar(20) not null);
Query OK, 0 rows affected (0.11 sec)

mysql> show tables;
+---------------------+
| Tables_in_gubeiqing |
+---------------------+
| gubeiqing_table     |
+---------------------+
1 row in set (0.01 sec)

接着给数据库新增列,基本简单语法是:ALTER TABLE 表名 add column 列名 列类型 是否为空;

mysql> desc gubeiqing_table;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| name  | varchar(20) | NO   |     | NULL    |       |
| age   | varchar(20) | NO   |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
2 rows in set (0.01 sec)

mysql> alter table gubeiqing_table add column job varchar(20) not null;
Query OK, 0 rows affected (0.26 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc gubeiqing_table;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| name  | varchar(20) | NO   |     | NULL    |       |
| age   | varchar(20) | NO   |     | NULL    |       |
| job   | varchar(20) | NO   |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

修改列名,基本简单语法是:ALTER TABLE 表名 change column 原列名 修改后的列名 列类型 是否为空;

mysql> desc gubeiqing_table;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| name  | varchar(20) | NO   |     | NULL    |       |
| age   | varchar(20) | NO   |     | NULL    |       |
| job   | varchar(20) | NO   |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

mysql> alter table gubeiqing_table change column job gbq_job varchar(20) not null;
Query OK, 0 rows affected (0.11 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc gubeiqing_table;
+---------+-------------+------+-----+---------+-------+
| Field   | Type        | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| name    | varchar(20) | NO   |     | NULL    |       |
| age     | varchar(20) | NO   |     | NULL    |       |
| gbq_job | varchar(20) | NO   |     | NULL    |       |
+---------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

删除刚刚新增的列,基本简单语法是:ALTER TABLE 表名 drop column 列名;

mysql> desc gubeiqing_table;
+---------+-------------+------+-----+---------+-------+
| Field   | Type        | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| name    | varchar(20) | NO   |     | NULL    |       |
| age     | varchar(20) | NO   |     | NULL    |       |
| gbq_job | varchar(20) | NO   |     | NULL    |       |
+---------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

mysql> alter table gubeiqing_table drop column gbq_job;
Query OK, 0 rows affected (0.11 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc gubeiqing_table;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| name  | varchar(20) | NO   |     | NULL    |       |
| age   | varchar(20) | NO   |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
2 rows in set (0.00 sec)

然后说一下模糊搜索,就比如现在要在数据库里查找zhangsan的信息,可是只记得zhang剩下的部分都不记得了,那么就可以使用模糊搜索,基本简单语法是:SELECT * from 表名 WHERE 字段 LIKE '模糊字段';

mysql> select * from gubeiqing_table where name like 'zhang%';
+----------+-----+
| name     | age |
+----------+-----+
| zhangsan | 20  |
+----------+-----+
1 row in set (0.01 sec)

%用来表示不记得的部分,是通配符。

除了%之外还有_表示任何单个字符,[ ]指定范围或集合中的任何单个字符,[^]不属于指定范围或集合的任何单个字符。

方便获取更多学习、工作、生活信息请关注本站微信公众号城东书院 微信服务号城东书院 微信订阅号
推荐内容
相关内容
栏目更新
栏目热门