display job Title, the difference between minimum and maximum salaries for those jobs which max salary within the range 12000 to 18000.
return jobs ;return the max salary for each #1 ;return #1 where #2 is  within the range 12000 to 18000 ;return the minimum salary of #3 ;return the maximum salary of #3 ;return the difference of #4 and #5 ;return the job Title of #3 ;return #6 , #7
['select', 'group', 'comparative', 'project', 'project', 'arithmetic', 'project', 'union']