1 Create table If Not Exists Employee (Id int, Company varchar(255), Salary int);2 3 insert into Employee (Id, Company, Salary) values (1, 'A', 2341);4 insert into Employee (Id, Company, Salary) values (2, 'A', 341);5 insert into Employee (Id, Company, Salary) values (3, 'A', 15);6 insert into Employee (Id, Company, Salary) values (4, 'A', 15314);7 insert into Employee (Id, Company, Salary) values (5, 'A', 451);8 insert into Employee (Id, Company, Salary) values (6, 'A', 513);9 insert into Employee (Id, Company, Salary) values (7, 'B', 15);
10 insert into Employee (Id, Company, Salary) values (8, 'B', 13);
11 insert into Employee (Id, Company, Salary) values (9, 'B', 1154);
12 insert into Employee (Id, Company, Salary) values (10, 'B', 1345);
13 insert into Employee (Id, Company, Salary) values (11, 'B', 1221);
14 insert into Employee (Id, Company, Salary) values (12, 'B', 234);
15 insert into Employee (Id, Company, Salary) values (13, 'C', 2345);
16 insert into Employee (Id, Company, Salary) values (14, 'C', 2645);
17 insert into Employee (Id, Company, Salary) values (15, 'C', 2645);
18 insert into Employee (Id, Company, Salary) values (16, 'C', 2652);
19 insert into Employee (Id, Company, Salary) values (17, 'C', 65);

 1 select 2      b.id,3      b.company,4      b.salary5 from 6     (select7            id,8            company,9            salary,
10            case @com when company then @rk:=@rk+1 else @rk:=1 end rk,
11            @com:=company
12     from
13            employee,
14            (select @rk:=0, @com:='') a
15     order by
16            company,salary
17     ) b
18 left join
19     (select
20            company,
21            count(1)/2 cnt
22      from
23            employee
24      group by company
25     ) c
26 on
27      b.company=c.company
28 where
29      b.rk in (cnt+0.5,cnt+1,cnt);