Calculate Records based on Field Content

[Jason Carter]

Hi All,

I have a table called "Vessel Logbook" which is used to record daily fuel consumption for our companies vessels.

I have 6 Fields "Vessel Name", "Date", "Consumption", "Loaded", "Transferred" and "R.O.B" (Remaining on Board).

What i am looking for is a calculation for the "R.O.B" field which will automatically calculate the R.O.B of the vessel for that day.

eg.

If Vessel Name = Vessel 1

R.O.B = Date - 1 (previous Day) - "Consumption" + "Loaded" - "Transferred"

to do this with 1 vessel i can do but as we have over 20 vessels i am stuck, can someone help with this?

[comment]

It would probably be best to lookup the previous balance, using a self-join relationship as described here:

http://fmforums.com/forum/topic/65083-running-balance/page__view__findpost__p__308701

[Jason Carter]

It would probably be best to lookup the previous balance, using a self-join relationship as described here:

http://fmforums.com/...post__p__308701

Thanks for your reply however i am new to Filemaker and i don't completely understand.

Is it possible to explain this method a little more?

[comment]

If you have a specific question, I'll try to answer.