Hello all I am trying to use the computed field to make some calculations based on other nodes and I'm by no means and sql novice even. What I am trying to accomplish is the following.

User creates a Program Node with values for registered users, length of program in minutes and hours.
Once created the user can track attendance for that program(using node reference) with how many participants there are, on submission it would show the amount of participant hours (length of program from Program node created in the first step X the total number of participants) it would also show the previous weeks participant hours as a comparison.

I'm not really sure how to accomplish this or the php/sql statements I would need. If you could get me pointed in the right direction that would be great.

Thank you so much.