Hi,
I have changed what you have suggested me
Here is my new query for PriceDiff:
PriceDiff: Abs([1st dec].[Price]-(SELECT TOP 1 Q.[Price] FROM [1st dec] AS Q WHERE Q.[Key] = mid([1st dec].[Key],1, instr(1, [1st dec].[Key], "/") - 1) & "/1/" & mid([1st dec].[Key], nz(instr(1, [1st...