Yep I think you will need use vba to loop through the records. Not all syntax is right but maybe something like this would work:
rs1 = Select * from Table ORDER BY StockID, Date, Time Asc
vChangeFlag = 0
vStockID = Null
vDate = Null
rs1.MoveFirst
Do Until rs1.EOFIf rs1!StockID = vStockID and rs1!Date = vDate then
If rs1!Change > 0.0169 OR vChangeFlag = 1 then
rs1.Update
rs1!ChangJump = rs1!HIgh - rs1!Low
rs1.Update
vChangeFlag = 1 (setting this means that all records after this one for same Stock and Date will need to do the calculation)
End If
Else
vChangeFlag = 0 (Set Flag to 0 on new Stock and Date)
If rs1!Change > 0.0169 then (This part processes the first record in the table or record with new Stock and Date)
rs1.Update
rs1!ChangJump = rs1!HIgh - rs1!Low
rs1.Update
vChangeFlag = 1 (setting this means that all records after this one for same Stock and Date will need to do the calculation)
End If
vStockID = rs1!StockID
vDate = rs1!Date
End IF
rs1.MoveNext
Loop