sql - 列出从事其部门赞助的一个项目以及从事非其部门赞助的一个项目的员工的姓名

Question

我的代码是

select name
from employee e, workon w
where e.empid = w.empid
and pid in
   (select pid 
    from workon
    where did in
         (select did
          from employee ee
          where e.did = ee.did))
group by name

但我知道这是不对的，因为我还需要找一个在他部门以外的项目中工作的人。问题是我不太确定该怎么做。

表员工

EMPID   NAME    SALARY  DID
1   kevin   32000   2
2   joan    46200   1
3   brian   37000   3
4   larry   82000   5
5   harry   92000   4
6   peter   45000   2
7   peter   68000   3
8   smith   39000   4
9   chen    71000   1
10  kim 46000   5
11  smith   46000   1

从事于

PID EMPID   HOURS
3   1   30
2   3   40
5   4   30
6   6   60
4   3   70
2   4   45
5   3   90
3   3   100
6   8   30
4   4   30
5   8   30
6   7   30
6   9   40
5   9   50
4   6   45
2   7   30
2   8   30
2   9   30
1   9   30
1   8   30
1   7   30
1   5   30
1   6   30
2   6   30
Project 

PID PNAME   BUDGET  DID
1   DB development  8000    2
2   network development 6000    2
3   Web development 5000    3
4   Wireless development    5000    1
5   security system 6000    4
6   system development  7000    1

Answer 1

select e.name
from employee e
where
    -- Projects in department
    exists (
        select *
        from 
            workon w
            join project p
                on w.pid = p.pid
                and p.did = e.did
        where w.empid = e.empid
    )
    -- Projects out of department
    and exists (
        select *
        from 
            workon w
            join project p
                on w.pid = p.pid
                and p.did != e.did
        where w.empid = e.empid
    )