-------------------帮助的使用----------------------
使用MySQL安装后自带的帮助文档
--按照层次看帮助
显示所有可供查询的的分类:contents
“类别名称”的方式针对用户感兴趣的内容做进一步的查看
example:
mysql> ? data types
--查看 MySQL 中都支持哪些数据类型
mysql> ? BINARY
--查看类型的具体介绍
Name: 'BINARY'
Description:
BINARY(M)
The BINARY type is similar to the CHAR type, but stores binary byte
strings rather than nonbinary character strings. M represents the
column length in bytes.
URL: https://dev.mysql.com/doc/refman/8.0/en/string-type-overview.html
--快速查阅帮助
快速查阅某项语法--MySQL对空格貌似比较敏感
example:
mysql> ? create table
--常用的网络资源
-------------------查看版本号----------------------
--1.使用命令行模式进入mysql会看到最开始的提示符
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 15
Server version: 8.0.0-dmr-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.
--2.命令行中使用status可以看到
mysql> status;
--------------
mysql Ver 14.14 Distrib 8.0.0-dmr, for Win64 (x86_64)
Connection id: 15
Current database:
Current user: root@localhost
SSL: Not in use
Using delimiter: ;
Server version: 8.0.0-dmr-log MySQL Community Server (GPL)
Protocol version: 10
Connection: localhost via TCP/IP
Server characterset: utf8
Db characterset: utf8
Client characterset: utf8
Conn. characterset: utf8
TCP port: 3306
Uptime: 12 hours 26 min 47 sec
Threads: 1 Questions: 118 Slow queries: 0 Opens: 292 Flush tables: 2 Open tables: 268 Queries per second avg: 0.002
--------------
--3.使用系统函数
mysql> select version();
+---------------+
| version() |
+---------------+
| 8.0.0-dmr-log |
+---------------+
1 row in set (0.00 sec)
--4. $ mysql --help | grep Distrib
mysql Ver 14.14 Distrib 5.1.69, for redhat-linux-gnu (x86_64) using readline 5.1
--5.5 包管理工具(根据不同系统 rh系列或则是bsd系列)
$ rpm -qa|grep mysql
qt-mysql-4.6.2-20.el6.x86_64
mysql-server-5.1.69-1.el6_4.x86_64
mysql-libs-5.1.69-1.el6_4.x86_64
mysql-5.1.69-1.el6_4.x86_64
mysql-devel-5.1.69-1.el6_4.x86_64
-------------------MySQL创建用户与授权方法----------------------
--在MySQL查看MySQL的安装目录
mysql> select @@basedir;
+------------------------------------------------+
| @@basedir |
+------------------------------------------------+
| C:\Program Files (x86)\MySQL\MySQL Server 5.1\ |
+------------------------------------------------+
1 row in set (0.00 sec)
--创建用户及授权
CREATE USER 'lin'@'localhost' IDENTIFIED BY 'mypass';
grant all on *.* to 'lin'@'localhost';
https://www.jb51.net/article/31850.htm
https://www.cnblogs.com/bethal/p/5512755.html
-------------------MySQL执行SQL脚本的方法----------------------
1.在命令行下(未连接数据库),输入 mysql -h localhost -u root -p123456 < F:\hello world\niuzi.sql (注意路径不用加引号的!!) 回车即可.
2.在命令行下(已连接数据库,此时的提示符为 mysql> ),输入
source F:\hello world\niuzi.sql (注意路径不用加引号的) 或者
\. F:\hello world\niuzi.sql (注意路径不用加引号的) 回车即可
-------------------MySQL支持的数据类型----------------------
--1.数值类型
如果超出类型范围的操作,会发生 “Out of range ”错误提示。
如果不显示指定宽度则默认为 int(11)。
一般配合 zerofill 使用,顾名思义,zerofill 就是用“0”填充的意思,也就是在数字位数不够
的空间用字符“0”填满。
--zerofill的使用
mysql> alter table t1 modify id2 int(5) zerofill;
+------------+-------