Create a chart with Invoice_ID as dimension.
This expression gives you only those having more than one color:
This expression gives you only those having total differ from items:
You can use the same approach and add list boxes with expressions that allow user to select such Invoices.
=aggr(Count(DISTINCT Item_color)>1 , Invoice_ID)
quite simple (and when I look at that now, quite obvious) solution
it works like a charm, now I have to test it on much more complex formulas
but, can someone tell me why this formula works as expression and not as calculated dimension? (it should behave the same, or at least that is what I understand)