mysql登录：方法1：使用Command Line Client登录，缺点：不显示报错信息
方法2：使用cmd登录（cmd的常用：查看ip地址：ipcongfi-----定时关机：shutdown -s -t 10800，3小时=180分钟=180*60秒=10800秒）1.切换到mysql\bin目录下2.mysql -u root -p
方法3：带ip地址的登录，可以是本机ip，也可以是远程mysql服务器的ip地址mysql -h 192.168.1.5 -u root -p
方法4：1.查看mysql当前端口号：show global variables like 'port';2.停止服务，更改端口号，my.ini，启动服务器3.mysql -u root -P 3307 -p4.查看mysql当前端口号：show global variables like 'port';
方法5：1.解决1130报错2.使用Navicat登录
数据的命令：创建库：create database 库名称；create database test1;create database if not exists test1;修改库：自行学习删除库：drop database 库名称；
创建表：create table 表名称 (字段名1 字段类型 字段长度 [字段约束],字段名2 字段类型 字段长度 [字段约束],字段名3 字段类型 字段长度 [字段约束]);
create table linux (cd datetime not null,ls varchar(10) default "yes",pwd int(4));insert into linux values("2019-5-31","today","4444");insert into linux values("2019-5-31","","4444");insert into linux values("2019-5-31",default,"4444");
插入数据：insert into 表名称 values(v1,v2,v3);insert into linux values("2019-5-31","today","4444");insert into linux values("2019-5-31 16:36:50","today","4444");insert into linux values("2019-5-32","today","4444");insert into linux values("2019-5-31","today","1234567890");insert into linux values("2019-5-31","today","12345678901");
insert into linux(cd,ls) values("2019-5-31","today");insert into linux values("2019-5-31","today",default);insert into linux values("2019-5-31","today","");insert into linux values("2019-5-31","today",null);
修改表字段类型：ALTER TABLE 表名 MODIFY 字段名 数据类型;alter table linux modify pwd int;alter table linux modify cd date;
修改表字段排序：ALTER TABLE 表名 MODIFY 字段名1 数据类型 FIRST;ALTER TABLE 表名 MODIFY 字段名1 数据类型 AFTER 字段名2;ALTER TABLE linux MODIFY pwd int(11) AFTER cd;ALTER TABLE linux MODIFY ls varchar(10) FIRST;
添加字段：ALTER TABLE 表名 ADD 新字段名 数据类型;ALTER TABLE 表名 ADD 新字段名 数据类型 [FIRST|AFTER 已存在字段名];ALTER TABLE linux ADD mkdir float;ALTER TABLE linux ADD rm double after cd;
删除字段：alter tabel 表名 drop 原有字段名;alter tabel linux drop column rm;
数据库字段的约束表达not null 非空约束default 默认约束primary key 主键约束auto_increment 自增长
create table linux (pwd int(4) primary key auto_increment,cd datetime not null,ls varchar(10) default "yes");
insert into linux values(1,"2019-6-3","123");insert into linux values(default,"2019-6-3","123");
以下是练习
create table employee (empid varchar(12) primary key comment "员工编号",name varchar(12) not null comment "员工姓名",sex int comment "性别",title varchar(8) comment "职称",birthday date comment "生日",depid varchar(10) comment "部门编号");
create table department (depid varchar(12) primary key comment "部门编号",depname varchar(8) comment "部门名称",info varchar(8) comment "部门简介",);
create table salary(empid varchar(12),basesalary int comment "基本工资",stationsalary int comment "岗位工资");
insert into employee values(1001,"张三","1","高级工程师","1975-1-1",111);insert into employee values(1002,"李四","0","助理工程师","1985-1-1",111);insert into employee values(1003,"王五","1","工程师","1978-1-1",222);insert into employee values(1004,"赵六","1","工程师","1979-1-1",222);
insert into department values(111,"生产部","1");insert into department values(222,"销售部","2");insert into department values(333,"人事部","3");
insert into salary values(1001,2200,1100);insert into salary values(1002,1200,200);insert into salary values(1003,1900,700);insert into salary values(1004,1950,700);
添加外键：alter table salary add constraint FK_ID foreign key(empid) REFERENCES emoloyee (empid);
alter table employee add constraint FK_DEPID foreign key(empid) REFERENCES department(empid);更改 表 员工表 添加 约束 约束名称employee 外键（员工表的empid） 关联 部门表（部门表的empid）
转载于:https://www.cnblogs.com/KSH1/p/11086949.html
相关资源：MySQL练习代码素材