Summarising multiple fields..?

[AliB]

Help please!

I have a lineItems table, which contains stockTable items and costs via lookups. The lineItems table has a calculated Summary field - Sum(lineTotal) - so when I do a find on a particular lineDescription, I can see the total value of sales for that particular item - great!

However, I would like to show - dynamically if possible - the top 10 selling items. I'm stuck on the best way to do this!?

I have a few Heath-Robinson-esque theories, but I'd like to do it right!

[AliB]

OK, so I've now added a relationship (by unique stockID) between stock and lineItems so that the Sum(lineItems) calculation within the lineItems table also appears as a calculated field in the stock table.

However, when I try and filter "to date" (i.e. sales total up to today) by adding AND today (stock) ≥ hireStartDate (from lineItems) to my relationship, the sum calculations dissapear.

What am I missing?