Mysql实现版本：
create table project(id varchar(10),name varchar(10));
create table hetong(id varchar(10),projectid varchar(10),hetongkuan varchar(10));
create table inmoney(id varchar(10),hetongid varchar(10),money varchar(10));
insert into project values("1","pro1");
insert into project values("2","pro2");
insert into project values("3","pro3");
insert into hetong values("1","1",1000);
insert into hetong values("2","1",2000);
insert into hetong values("3","2",3000);
insert into inmoney values("1","1",500);
insert into inmoney values("2","1",300);
insert into inmoney values("3","2",200);
insert into inmoney values("4","2",300);
insert into inmoney values("5","3",100);
一个项目有多个合同，一个合同有多个收款记录
(1)每个项目的和同款总数结果
select project.id,project.name,sum(hetong.hetongkuan)
from project left join hetong on project.id=hetong.projectid
group by hetong.projectid
order by project.id;
--------------------------
编号 名称 总合同款
1 pro1 3000
2 pro2 3000
3 pro3 null
--------------------------
(2)每个项目已收款总数结果
select project.id,project.name,sum(inmoney.money)
from project,hetong,inmoney
where project.id=hetong.projectid and hetong.id=inmoney.hetongid
group by hetong.projectid;
---------------------------
编号 名称 合同已收款
1 pro1 1300
2 pro2 100
3 pro3 null
---------------------------
(3)每个项目合同总数，已收总数结果
select aa.id,aa.name,sum(aa.hetongkuan),sum(aa.a) from (select project.id,project.name,hetong.hetongkuan,sum(inmoney.money) as a
from project,hetong,inmoney
where project.id=hetong.projectid and hetong.id=inmoney.hetongid
group by inmoney.hetongid) as aa
group by aa.id
---------------------------
编号 名称 总合同款 合同已收款
1 pro1 3000 1300
2 pro2 3000 100
---------------------------
Oracle实现版本：
drop table project;
drop table hetong;
drop table inmoney;
create table project(id varcha2r(10),name varchar2(10));
create table hetong(id varchar2(10),projectid varchar2(10),hetongkuan number(10));
create table inmoney(id varchar(10),hetongid varchar2(10),money number(10));
insert into project values(\'1\',\'pro1\');
insert into project values(\'2\',\'pro2\');
insert into project values(\'3\',\'pro3\');
insert into hetong values(\'1\',\'1\',1000);
insert into hetong values(\'2\',\'1\',2000);
insert into hetong values(\'3\',\'2\',3000);
insert into inmoney values(\'1\',\'1\',500);
insert into inmoney values(\'2\',\'1\',300);
insert into inmoney values(\'3\',\'2\',200);
insert into inmoney values(\'4\',\'2\',300);
insert into inmoney values(\'5\',\'3\',100);
(1)
select p.id,p.name,sum(h.hetongkuan)
from project p
left outer join hetong h
on p.id=h.projectid
group by p.id,p.name;
(2)
select project.id,project.name,sum(inmoney.money)
from project,hetong,inmoney
where project.id=hetong.projectid and hetong.id=inmoney.hetongid
group by project.id,project.name;
(3)
select aa.id,aa.name,sum(aa.hetongkuan),sum(aa.a) from (select p.id,p.name,h.hetongkuan,sum(m.money) as a
from project p,hetong h,inmoney m
where p.id=h.projectid and h.id=m.hetongid
group by p.id,p.name,h.hetongkuan) aa
group by aa.id,aa.name;