I'm trying to do a report to calculate how much people owe the landlord in electricity bills.

To do this i need to subtract the electricity usage reading of a month ago from the reading of today (and hence get the reading for this month)

Any help on how I could do this on Crystal reports XI in a formula maybe?

Thank you very much

Edit: I connected crystal Reports to an OBDC data source that is produced by Factory Talk. It is an array of a number of tags with different values.

Edited by keristos - 27 Sep 2011 at 1:23am