display the department ID, full name (first and last name), salary for those employees who is highest salary in every department.
return employees ;return department  ;return salary  of #1 ;return #1 where #3 is  highest for each #2 ;return department  ID of #4 ;return full name of #4 ;return salary  of #4 ;return #5 ,  #6 ,   #7
['select', 'select', 'project', 'group', 'project', 'project', 'project', 'union']