Question

如何显示员工人数第二高的项目名称？

关系模式，具有主键和外键（适用时）：

Employee(Eid,Ename,Address,city,Doj,salary) Project(Pid,Location,Pname,Mng,Client,Branch)
Works(Eid,Pid)

Eid和Pid in Works是ForeignKey。 eid和pid分别是员工和项目中的主键

select count (*) , pname
from project natural join work
group by pname;

但这只会提供根据项目的员工人数...而不是最大员工人数

select max as ex1
from (Select count(*) as ex1
      from works
      where PID in ( select distinct pid from works);

我正在linux-oracle中尝试

Answer 1

SELECT COUNT(W.Eid) AS TotalEmployees, P.pname 
FROM Works W
     INNER JOIN Project P ON W.Pid = P.Pid   
GROUP BY P.Pid
ORDER BY TotalEmployees desc
OFFSET 1 ROWS FETCH NEXT 1 ROWS ONLY

Answer 2

好的，我认为下面的SQL将返回您想要的内容（2号项目的名称和员工编号）：

select * from 
(
select
    p.pname,
    count(1) as cc
from
    work w
join
    project p on w.pid = p.pid
join
    employee e on w.eid = e.eid
group by
    p.pname
order by cc desc limit 2
) tmp order by cc asc limit 1

如何将COUNT和MAX组合使用但按组使用？

2 个答案: