Mysql 库表操作初识

时间:2021-09-24 01:07:29

Mysql 库表操作初识

终端登录mysql

这里只演示win下, cmd 终端. 至于怎么在win下, linux, mac安装, 感觉这是一个入门级的百度搜索问题, 安装都搞不定, 确实有点尴尬, 好尴尬呀.

-- win   R 输入cmd 进入控制台
C:Userschenjie> mysql  -u root -p  -- 回车
Enter password: ********  -- 回车

-- 成功进入了mysql客户端, 如果登录失败, 要么就是密码不对, 或者是服务没有开启.
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 19
Server version: 5.7.17-log MySQL Community Server (GPL)

Copyright (c) 2000, 2016, 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.

-- 打印 "hello,world!" 测试
mysql> select "hello, world!";
 --------------- 
| hello, world! |
 --------------- 
| hello, world! |
 --------------- 
1 row in set (0.00 sec)

-- test
mysql> select now();
 --------------------- 
| now()               |
 --------------------- 
| 2019-10-06 14:11:41 |
 --------------------- 
1 row in set (0.00 sec)

mysql> select curdate() as "今日日期";
 -------------- 
| 今日日期     |
 -------------- 
| 2019-10-06   |
 -------------- 
1 row in set (0.00 sec)

mysql> select database();
 ------------ 
| database() |
 ------------ 
| NULL       |
 ------------ 
1 row in set (0.05 sec)

-- 查看所有的数据库
mysql> show databases;
 -------------------- 
| Database           |
 -------------------- 
| information_schema |
| cj                 |
| flask_db           |
| from_pdm           |
| mysql              |
| new_house          |
| performance_schema |
| python_test_1      |
| sql_advance        |
| stock_db           |
| sys                |
| test1              |
 -------------------- 
19 rows in set (0.04 sec)

mysql> show variables like 'port';
 --------------- ------- 
| Variable_name | Value |
 --------------- ------- 
| port          | 3306  |
 --------------- ------- 
1 row in set (0.10 sec)

-- 查看数据库编码
mysql> show variables like "character%";
 -------------------------- ---------------------------------- 
| Variable_name            | Value                            |
 -------------------------- ---------------------------------- 
| character_set_client     | utf8mb4                          |
| character_set_connection | utf8mb4                          |
| character_set_database   | utf8                             |
| character_set_filesystem | binary                           |
| character_set_results    | utf8mb4                          |
| character_set_server     | utf8                             |
| character_set_system     | utf8                             |
| character_sets_dir       | C:AppServMySQLsharecharsets |
 -------------------------- ---------------------------------- 
8 rows in set (0.05 sec)

-- 查看某用户的权限
mysql> show grants for 'root'@'localhost';
 --------------------------------------------------------------------- 
| Grants for [email protected]                                           |
 --------------------------------------------------------------------- 
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION |
| GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION        |
 --------------------------------------------------------------------- 
2 rows in set (0.10 sec)

-- 查看数据库当前连接数, 并发数
mysql> show status like 'Threads%';
 ------------------- ------- 
| Variable_name     | Value |
 ------------------- ------- 
| Threads_cached    | 1     | -- 此线程中的空闲线程数
| Threads_connected | 4     |
| Threads_created   | 5     | -- 最近一次启动服务,做创建的线程数
| Threads_running   | 1     | -- 当前激活线程数 
 ------------------- ------- 
4 rows in set (0.05 sec)

-- 查看数据文件存放路径
mysql> show variables like "