刘道平的专栏

 create database teacher;use teacher;create table teacher(       id int primary key identity(1,1),       tname varchar(50),       tage int,       tsex varchar(10),       class varchar(10),       keche

 use student;select *from student;insert into student(same) values(胡利华);select *from student;insert into student values(sa,12,null);insert into student values(sb,13,null);insert into student val

--聚合函数use pubsgoselect avg(distinct price)  --算平均数from titleswhere type='business'go use pubsgoselect max(ytd_sales)  --最大