I haven't used VLOOKUP that often, but as I understand it, the function works on a table where it searches for a value in the left-hand column, and then displays the corresponding value of the same row in any other column specified in that table.
For my part the clue must be in the use of a table. The table has to be together, and cannot be spread over different worksheets. So I think your first task is to find a way to combine all the data from the different columns into one table, use the VLOOKUP function to search for and find discrepancies, then use the displayed result to reference the appropriate cells in either of the two worksheets.
I hope that helps, but perhaps others here will have better ideas.
I am having trouble understand the vlookup function in excel. I need to be able to compare the values of two columns (customer number and salesperson number) in two worksheets. If the two columns in each worksheet do not match I want to return the customer number in a third worksheet. I have tried to follow vlookup tutorials online, but have not been able to make vlookup work the way I need it to. Can anyone help me?