MYSQL简单应用

1.建立一个数据库

create database vfast;

2.新建一个用户表

create table employee(employee_id int,name char(12),gerder enum('M','F'),dent_id set("1","2","3","4"),join_time date,salary float,phone char(11),address char(40),description text);

3.建立用户记录

insert into tablename values(1,"name","F/M","1/2/3/4","2000-01-01",1234.56,"13800000001","address","description")

4.实现sql查询

    按名字查找

    select * from tablename where name="employeename";

    按照薪水>查找

    select * from tablename where salary>4300 and salary<9000;

    查找每个部门的人数

    select dent_id,count(*) as dentsum from tablename group by dent_id;

    每个部门的平均薪资

    select dent_id,avg(salary) as avgsalary from tablename group by dent_id;

    描述字段为空的员工

    select * from tablename where description is null;

    求出每个部门女员工工资最高的职工的薪水

    select max(salary) from tablename where gerder='F' group by dent_id;

    名字以l开头的员工个数

    select * from tablename where name like "l%"