Sorry if this is in the wrong forum; I am relatively new to Access, and wasn't sure if this is query-related or not. I am trying to set up a database in Access 2013 for vehicle maintenance and fuel tracking. I have a table called "fuel" where I enter fuel purchases (including mileage at fillup, total cost, total gallons, etc.)
I want to have a field in this table called "MPG". This field, for a given row, will take the number from the "mileage" field and find the total miles traveled by looking back through the previous rows and finding the next highest mileage. It will then divide this difference by the number entered in the "gallons" field for the current row, and this will give the number for the "MPG" field.
I'm sure I'm making this sound way more complicated than it is - I'm pretty sure everyone knows how to do an MPG calculation - and I could do it with Excel by just using VLOOKUP or INDEX/MATCH (or even just by assuming that all fuel entries are chronological and looking back at the previous row). Just not sure how to accomplish this in Access!