with tmp as (
select to_date('20100302','yyyymmdd') sale_date, '001' employee_id, 'C1' client_id, 'P1' product_id from dual
union all
select to_date('20100302','yyyymmdd') sale_date, '001' employee_id, 'C1' client_id, 'P2' product_id from dual
union all
select to_date('20100302','yyyymmdd') sale_date, '002' employee_id, 'C1' client_id, 'P1' product_id from dual
union all
select to_date('20100302','yyyymmdd') sale_date, '002' employee_id, 'C2' client_id, 'P1' product_id from dual
union all
select to_date('20100302','yyyymmdd') sale_date, '002' employee_id, 'C2' client_id, 'P2' product_id from dual
union all
select to_date('20100302','yyyymmdd') sale_date, '002' employee_id, 'C1' client_id, 'P1' product_id from dual
) 
select mt.sale_date,mt.employee_id,mt.client_id,mt.product_id
from tmp mt,(
select sale_date,employee_id,client_id,count(distinct product_id)
from tmp
group by sale_date,employee_id,client_id
having count(distinct product_id) > 1
) st
where mt.sale_date = st.sale_date
and mt.employee_id = st.employee_id
and mt.client_id = st.client_id;

------解决方案--------------------
select *
from A
where (sale_date, employee_id,client_id) in
(select sale_date, employee_id,client_id
from A
group by sale_date, employee_id,client_id
having count(*)>1)

------解决方案--------------------
分区查？over是什么意思？

不懂，帮顶  我也想知道如何弄...

------解决方案--------------------
  1.2.3楼都对！
  但是1楼好！效率要高些！

------解决方案--------------------
SQL code
create table a(
sale_date date,
employee_id char(4),
client_id char(4),
product_id char(4)
);

insert into a(sale_date,employee_id,client_id, product_id) values(to_date('20100302','yyyymmdd'), '001', 'C1', 'P1');
insert into a(sale_date,employee_id,client_id, product_id) values(to_date('20100302','yyyymmdd'), '001', 'C1', 'P2');
insert into a(sale_date,employee_id,client_id, product_id) values(to_date('20100302','yyyymmdd'), '002', 'C1', 'P1');
insert into a(sale_date,employee_id,client_id, product_id) values(to_date('20100302','yyyymmdd'), '002', 'C2', 'P1');
insert into a(sale_date,employee_id,client_id, product_id) values(to_date('20100302','yyyymmdd'), '002', 'C2', 'P2');
insert into a(sale_date,employee_id,client_id, product_id) values(to_date('20100302','yyyymmdd'), '002', 'C1', 'P1');

SELECT to_char(a1.sale_date,'yyyymmdd'), a1.employee_id, a1.client_id, a1.product_id, count(a1.product_id) product_count
FROM a a1
GROUP BY to_char(a1.sale_date,'yyyymmdd'), a1.employee_id, a1.client_id, a1.product_id
HAVING COUNT(a1.product_id)>=2;

------解决方案--------------------
SQL code

SQL> edi
已写入 file afiedt.buf

  1  select to_char(sale_date,'yyyymmdd') sale_date,employee_id,client_id,product_id from
  2  tb a where exists(select 1 from tb where employee_id=a.employee_id and client_id=a.client_id
  3  group by employee_id,client_id
  4* having count(1)>=2)
SQL> /

SALE_DAT EMPLO CLIEN PRODU
-------- ----- ----- -----
2010