4) From the CREW table, find all distinct EMP_NUMs that have CROW_JOB=Pilot, but NOT Copilot

CHAR TRIP EMP NUM CREW JOB 10001 10002 10003 10003 10004 10005 10006 10007 10007 10008 10009 10010 10011 10011 10012 10013 10014 10015 10015 10016 10016 10017 10018 104 Pilot 101 Pilot 105 Pilot 109 Copilot 106 Pilot 101 Pilot 109 Pilot 104 Pilot 105 Copilot 106 Pilot 105 Pilot 108 Pilot 101 Pilot 104 Copilot 101 Pilot 105 Pilot 106 Pilot 101 Copilot 104 Pilot 105 Copilot 109 Pilot 101 Pilot 104 Copilot