MySQL SQL语句练习.doc

MySQL? SQL语句练习：1.建库建表--create database companycreate database company;use company;--create tables--部门表create table dept(deptno int(3) primary key,dname varchar(14),loc varchar(13));--雇员表create table emp(empno int(4) not null primary key,ename varchar(10),job varchar(10),mgr int(4),hiredate datetime,sal double,comm double,deptno int(3),foreign key(deptno) references dept(deptno));--工资级别表create table salgrade(grade int(3) primary key,losal int(3),hisal int(3));?----------------------------------------------------------------------------------------------------------------------------------------2.插入数据（进行初始化）use company;--往部门表中查数据insert into dept values(10,Accounting,New York);insert into dept values(20,Research,Dallas);insert into dept values(30,Sales,Chicago);insert into dept values(40,Operations,Boston);insert into dept values(50,Admin,Washing);--往雇员表中插数据insert into emp values(7369,Smith,Clerk,7902,1980-12-17,800,0,20);insert into emp values(7499,Allen,Salesman,7698,1981-2-20,1600,300,30);insert into emp values(7844,Turner,Salesman,7499,1981-9-8,1500,0,30);insert into emp values(7698,Tom,Manager,0,1981-9-8,6100,600,40);insert into emp values(7876,Adams,Clerk,7900,1987-5-23,1100,0,20);insert into emp values(7900,James,Clerk,7698,1981-12-3,2400,0,30);insert into emp values(7902,Ford,Analyst,7698,1981-12-3,3000,null,20);insert into emp values(7901,Kik,Clerk,7900,1981-12-3,1900,0,30);--往工资级别表中插数据insert into salgrade values(1,700,1200);insert into salgrade values(2,1201,1400);insert into salgrade values(3,1401,2000);insert into salgrade values(4,2001,3000);insert into salgrade values(5,3001,5000);insert into salgrade values(6,5001,10000);------------------------------------------------------------------------------------------------------------------------------------3.必会的5个组函数：max,min,avg,sum,count 要牢牢记住---------------------------------------------------------------------------------------------------------------