Comparing unsorted data across separate files

I need an automated way to compare the 2 sheets to make sure no equipment gets missed for ordering. I have to compare an order for equipment against an inventory of equipment to make sure everything is getting ordered. In my inventory sheet all the serial numbers are in column E, the data is sorted by column C which has the location info. The order sheet has the serial numbers in column G, sorted by location in column C. The serial number columns are not sorted the same way so a direct comparison can't be done.