I have a table to report fuel sale in 6 pumps, and 3 types of fuel for each pump; how can I put the previous reading of the number of gallons sold as the initial value, having two conditions, the number of the pump and the type of fuel?, The columns are: id, date, pump number, fuel type, current reading, previous reading. Thank you for your answers
Thanks Steve, I still haven’t been able to find the expression that helps me get the last value (147,001) of pump 3, diesel, could you help me?!
Thank you very much Steve, it works perfectly.