If two cells match, return value from third

Question

Here\'s a simple explanation of what I\'m having trouble with.

Column A: List of 2300 order numbers
Column B: Email Address associated with an order number
C

Answer 1

All you have to do is write an IF condition in the column d like this:

=IF(A1=C1;B1;" ")

After that just apply this formula to all rows above that one.