MS Excel automatically changes cell variables

Question

I'm using the formula
=Lookup(B2,Sheet2:D2:Sheet2:D9,Sheet2:A2:Sheet2:D9)
to search the value of B column in current Sheet in Sheet2's D column and then return the value of Sheet2's A column in the same row. When I expand lower corner of the cell to autofill 500 cells vertically, I see Excel has incremented B2:B500 as well as D2,D9,A2,A9 (those of Sheet2) as well. I don't want the latter to happen. In fact I want Excel NOT TO CHANGE D2,D9,A2,A9 in the formula.
What can I do?

Answer 1

Your problem is to do with the difference between relative and absolute references.

Relative references change when you copy a formula from one cell to another. If you enter =A1 in B1 and copy it to B2 it will now be =A2.

Absolute references don't change when you copy them. Enter =$A$1 in B2, then copy it to B2 and it will still be =$A$1

A "$" before the column reference anchors the column. A "$" before the row reference anchors the row. A $ before both anchors a specific cell.