Mysql 在SQL中从多对多关系中查找最大值

我有三张桌子-
员工-具有列-id、姓名、工资
项目-具有列-id、名称、预算
赋值-有列-empId，pid （这些列分别指员工和项目）

我希望SQL查询返回每个项目中工资最高的员工

结果集应该类似于-

Project id|Employee Name|Salary
     1    |      B      | 2000
     2    |      D      | 4000
     3    |      C      | 500

我编写了以下SQL。但是它把所有的行都还给了我。有什么不对劲吗

select p.id, p.name, e.id, e.name, e.salary
FROM 
(
    select e.id, MAX(e.salary) 
    from employee e
    join assignment a on e.id = a.empId
    join project p on p.id = a.pid
    group by e.id
 ) as EmpMAX
 join Employee e on EmpMAX.id = e.id
 join assignment a on a.empId = e.id
 join project p on p.id = a.pid

我参考了下面的链接来获得SQL

---

我使用的是MySQL

可能最简单的方法是

子字符串\u index（）

`group\u concat（）`技巧：

注意：如果有多个员工的工资相同，则只选择一名员工

SELECT p.*,e.* 
  FROM project p 
  JOIN assignment a 
    ON a.pid = p.id 
  JOIN employee e 
    ON e.id = a.empid 
  JOIN 
     ( SELECT p.id
            , MAX(salary) max_salary
         FROM project p 
         JOIN assignment a 
           ON a.pid = p.id 
         JOIN employee e 
           ON e.id = a.empid
        GROUP
           BY id
     ) x
    ON x.id = p.id
   AND max_salary = e.salary;

注意：如果有多个员工具有相同（最高）工资，则选择多个员工

select p.projid,
       substring_index(group_concat(e.name order by e.salary desc), ',', 1) as empname,
       max(salary)
from employee e join
     assignment a
     on e.id = a.empId
group by p.projid;

SELECT p.*,e.* 
  FROM project p 
  JOIN assignment a 
    ON a.pid = p.id 
  JOIN employee e 
    ON e.id = a.empid 
  JOIN 
     ( SELECT p.id
            , MAX(salary) max_salary
         FROM project p 
         JOIN assignment a 
           ON a.pid = p.id 
         JOIN employee e 
           ON e.id = a.empid
        GROUP
           BY id
     ) x
    ON x.id = p.id
   AND max_salary = e.salary;