Sub aggregation

[#1]

Hi,

I have a few traders, each trades different types of instruments. Each trade gets a deal ID.

There are deals (swap trades) that have both positive and negative values to the deal, i.e. the deal has two lines in the table.

I'd like to net the each deal values and then calculate the absolute total values for each trader.

Where is the best place to add that sub aggregation - in the table load script (how?) or as an expression in a chart object?

I created a separate table with just the deal ID and trade amounts. Then wanted to show each trader's total absolute trade amount.

I tried the latter with:

Aggr(DISTINCT Sum(Trade_Amount),deal_ID)

But got one single aggregation.

Thanks!

Michael