How to do a VLOOKUP/IF statement to get values

If serial number in SN1 column is in the SN2 column then I need to enter the volume figures in column C into the empty column (Col D). Data is shown below with columns ABCD.

SN1 (Col A) 
3249407142
3224017625
3249407142
3249407193
3249407223

..........
SN2 (Col B)
3249407274
3249407282
3647657000
3647658457
3849606742
............

Volume (Col C)
2794
0
50909
45592
67584
10668
81353
............

The empty column where figures will be entered is column D.