select e.emp_no,s.salary,e.last_name,e.first_name
from
employees e
join 
salaries s on e.emp_no=s.emp_no 
and s.salary = 
(
     select s1.salary
     from 
     salaries s1
     join
     salaries s2 on s1.salary<s2.salary 
     group by s1.salary
     having count(distinct s2.salary)=1
 )