I am trying the following formula and my return is 0-Jan-00

=MAX(IF($G$2:$G$6239=$L7,$B$2:$B$6239,0))

Col G contains all vehicle numbers, Col L is the vehicle #, Col B contains all fuel transaction dates for that vehicle.
I am trying to find the MIN & MAX dates to do a VLOOKUP for the odometer reading in Col E for each MAX & MIN date to get total mileage for that month. My return is 0-Jan-00. The file is quite large, over 7,000 lines of data, I can send a smaller example if needed. Thanks.