Calculations on previous and current fields in Memento Database fields

[Richard Dearth]

I would like to know if you can do calculations on previous and current fields in Memento Database fields.

If so how do you do it.  Thanks in advance...

[Suthee T.]

I'm looking for this function, too.  

Not sure if it's the same thing as Richard  is looking for, but I'm looking for the way to have the 'mass calculations' fields available  as a value in the fields calculation.

I am trying to create stock quantity calculation field.  It would be nice to have something like this :

(sum(#{balance}) + #{in_qty}) - #{out_qty}

or

(#{mass_calculation_of_balance} + #{in_qty}) - #{out_qty}

or

(previous(#{balance}) + #{in_qty}) - #{out_qty}

[Yan Lin]

Does it work? It doesn't work on mine...