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建立数据表(表3-6):
create table jbqk(number char(8)not null primary key, name char(8)not null, sex char(2)not null, birthday datetime, department char(12));
添加新列:
alter table jbqk add 成绩 decimal(3,0);
删除列:
alter table jbqk drop column 成绩;
插入数据:
一条:
insert intojbqk(number, name, sex, birthday, department)values('0022102','王雪丽','女','1981-3-5','电子系');多条:
insert intojbqk(number, name, sex, birthday, department)select'0022103','王丽','女','1981-3-5','电子系' UNION ALL
select'0022104','王雪','女','1981-3-5','电子系' UNION ALL
select'0022105','王雪丽','女','1981-3-5','电子系'
删除数据:
delete from jbqk
where name='王丽';
修改数据:
update jbqk set department='计算机系'
where name = '王雪';
单表查询:
select number,name,department from jbqk
where department='电气1'
/*group by having
order by [asc|desc]*/
order by number asc
select number,name,department from jbqk
where name like '%东';
select * from sle_course
where score between 80 and 85;
select avg(score)from sle_course;
多表查询:
select jbqk.number,jbqk.name,course.c_name,sle_course.score,teacher.t_name from jbqk,course,sle_course,teacher
where jbqk.number=sle_course.number
course.t_number=teacher.t_number;
and sle_course.c_number=course.c_number and