--一、现有学生表student，班级表classInfo，表结构如下：
--student表：sid学号，sname姓名，sex性别，birthday生日，age入学年龄，smoney缴费，cid班级ID
--classInfo表：班级编号cid，班级名称cname
--建表
drop table student cascade constraint;
drop table classinfo cascade constraint;
create table student(
sid number(6) constraint pk_stu_sid primary key,
sname varchar2(20),
sex varchar2(4),
birthday date,
age number(2),
smoney number(7,2),
cid number(4)
);
create table classinfo(
cid number(4) constraint pk_cls_cid primary key,
cname varchar2(20)
);
alter table student add constraint fk_stu_cls_cid foreign key(cid) references classinfo(cid);
insert into classinfo values(1101,'工商管理');
insert into classinfo values(1102,'计算机');
insert into classinfo values(1103,'会计');
insert into classinfo values(1104,'药品');
insert into student values(110001,'小明','男',to_date('1999-9-9','yyyy-mm-dd'),10,11220.50,1103);
insert into student values(110002,'小张','女',to_date('1991-6-9','yyyy-mm-dd'),19,10000.00,1102);
insert into student values(110003,'小红','女',to_date('1996-7-3','yyyy-mm-dd'),14,8800.00,1102);
insert into student values(110004,'张三','男',to_date('1996-2-1','yyyy-mm-dd'),14,6600.00,1102);
insert into student values(110005,'小花','女',to_date('1994-6-7','yyyy-mm-dd'),16,11440.50,1101);
insert into student values(110006,'王五',null,to_date('1991-12-5','yyyy-mm-dd'),20,11440.50,1101);
commit;
select * from student;
select * from classinfo;
--1、
查询入学年龄在18-20的女生或者未输入性别的学生信息，且年龄小的排在后面。
select * from student where age between 18 and 20 and (sex='女' or sex is null);
--2、
查询班级名称、学生姓名、性别、缴费（要求显示单位：元），相同班级的要放在一起，再按姓名升序排列。
select c.cname,s.sname,s.sex,s.smoney||'元' smoney from student s
join classinfo c on s.cid=c.cid order by c.cname,s.sname;
--3、
查询各班名称和人数。
select cname,count(*) from classinfo c join student s on c.cid=s.cid group by cname;
--4、
查询各班名称和人数，但人数必须不少于2，且人数多的放在前面。
select cname,count(*) from classinfo c join student s on c.cid=s.cid
group by cname having count(*)>=2 order by count(*) desc;
--5、
查询1980年出生的有哪些学生。
select * from student where to_char(birthday,'yyyy')='1980';
select * from student where to_char(birthday,'yyyy')='1991';
--6、
查询男生和女生人数，没有输入性别的当作男生计算。
select sex,count(*) from (select nvl(sex,'男') sex from student) group by sex;
--7、
查询没有人员的班级。
select * from classinfo where cid not in(select distinct cid from student);
--8、
查询入学年龄在20以上的学生信息。
select * from student where age>20;
select * from student where age>=20;
--9、
查询班级平均入学年龄在20及以上的班级名称和平均年龄。
select * from classinfo c join (select cid,avg(age) avg_age from student group by cid) t
on c.cid=t.cid where avg_age>=20;
select * from classinfo c join (select cid,avg(age) avg_age from student group by cid) t
on c.cid=t.cid where avg_age>=15;
--二、现有
--部门表bm：bid部门编号，bname名称
--人员表ry：rid人员编号，rname名称，bid部门编号
--工资表gz：rid人员编号，sal工资金额，rq发放日期
--建表
drop table bm cascade constraint;
drop table ry cascade constraint;
drop table gz cascade constraint;
create table bm(
bid number(4) constraint pk_bm_bid primary key,
bname varchar2(10)
);
create table ry(
rid number(4) constraint pk_ry_rid primary key,
rname varchar2(20),
bid number(4)
);
create table gz(
rid number(4),
sal number(7,2),
rq date
);
alter table ry add constraint fk_ry_bm_bid foreign key(bid) references bm(bid);
alter table gz add constraint fk_gz_ry_rid foreign key(rid) references ry(rid);
insert into bm values(1001,'销售');
insert into bm values(1002,'后勤');
insert into ry values(1101,'tom',1001);
insert into ry values(1103,'barbie',1001);
insert into ry values(1102,'jim',1002);
insert into gz values(1101,1200.5,sysdate);
insert into gz values(1101,1200.5,sysdate);
insert into gz values(1102,2000,sysdate);
insert into gz values(1103,5000,sysdate);
select * from bm;
select * from ry;
select * from gz;
--1、
查询员工姓名、部门名称和个人总工资。
select r.rname,b.bname,g.sal from bm b join ry r on b.bid=r.bid
join (select rid,sum(sal) sal from gz group by rid) g on g.rid=r.rid;
--2、
查询本月发了2笔以上工资的员工信息。
select * from ry r join
(select rid,to_char(rq,'yyyy-mm') rq,count(sal) sals from gz group by rid,rq) t
on r.rid=t.rid where t.rq=to_char(sysdate,'yyyy-mm') and sals=2;
--3、
查询各部门的总工资。ry.bid group by bm.bname;
select bname,sum(sal) from bm b join ry r on b.bid=r.bid join gz g on r.rid=g.rid group by bname;
--4、
查询2009年8月份各部门工资最高的员工信息，显示部门名称、员工姓名和员工工资。
select * from
(select b.bid,max(g.sal) sal from bm b join ry r on b.bid=r.bid
join (select rid,to_char(rq,'yyyy-mm') rq,sum(sal) sal from gz group by rid,rq) g on g.rid=r.rid
group by b.bid,b.bname) t1
join
(select b.bid,b.bname,r.rid,r.rname,g.sal from bm b join ry r on b.bid=r.bid
join (select rid,to_char(rq,'yyyy-mm') rq,sum(sal) sal from gz group by rid,rq) g on g.rid=r.rid) t2
on
t1.bid = t2.bid and t1.sal=t2.sal;
--一、现有学生表student，班级表classInfo，表结构如下：
--student表：sid学号，sname姓名，sex性别，birthday生日，age入学年龄，smoney缴费，cid班级ID
--classInfo表：班级编号cid，班级名称cname
--1、
把新进的学生Tom，其学号为x009，年龄19，分配到5班。
--insert into student values(009,'tom',null,null,19,null,5);
insert into student values(009,'tom',null,null,19,null,1103);
--2、
把1班的前5个人分到2班。
select * from student;
update student set cid = 1102
where sid in (select * from (select sid from student where cid=1101 order by sid) where rownum<=5);
select * from student;
--3、
把学生需要的缴费降低5%。
select * from student;
update student set smoney = smoney*0.95;
select * from student;
--4、
删除年龄不满18岁的学生信息。
select * from student;
delete from student where age < 15;
select * from student;
--5、
查询1990年以前出生的有哪些学生。
select * from student where to_char(birthday,'yyyy')<1990;
select * from student where to_char(birthday,'yyyy')<2000;
--6、
查询班级平均入学年龄在20及以上的班级名称和平均年龄。
select * from classinfo c join
(select cid,avg(age) from student group by cid) t
on c.cid=t.cid;
--二、现有
--部门表bm：bid部门编号，bname名称
--人员表ry：rid人员编号，rname名称，bid部门编号
--工资表gz：rid人员编号，sal工资金额，rq发放日期
--要求：用显式事务实现给销售部中工资>5000的员工降薪5%，同时，工资<1000的员工涨薪10%。
--select * from gz;
--update gz set sal=sal*0.95 where rid in (select r.rid from bm b join ry r on b.bid=r.bid join gz g on g.rid=r.rid where sal >2000);
--update gz set sal=sal*1.1 where rid in (select r.rid from bm b join ry r on b.bid=r.bid join gz g on g.rid=r.rid where sal <2000);
--select * from gz;
declare
cursor c is
select b.bid, r.rid, g.sal
from bm b
join ry r on b.bid = r.bid
join gz g on g.rid = r.rid;
v_temp c%rowtype;
begin
open c;
loop
fetch c
into v_temp;
exit when(c%notfound);
if (v_temp.sal > 5000) then
update gz set sal = sal * 0.95 where rid = v_temp.rid;
commit;
dbms_output.put_line('工资大于5000降薪5%--' || v_temp.sal);
elsif (v_temp.sal < 1000) then
update gz set sal = sal * 1.1 where rid = v_temp.rid;
commit;
dbms_output.put_line('工资小于1000涨薪10%--' || v_temp.sal);
end if;
end loop;
close c;
end;