I'm maintaining a Delphi application since a few days.
The customer wants to add a percentage column to a DBGrid, now showing a "Quantity" column. Of course the percentage would be the 
Row quantity / Total Quantity \* 100

I cannot modify the underlying TADOTable since it is used elsewhere in the code, but I tried to add a calculated field to the TADOTable - but is seems the calculated field cannot have a value based on an aggregate value (i.e. sum of quantity).

I succeeded in adding an empty column to the DBGrid, but is there any way to populate the % values in each row ?