Compare two columns A & C and copy B values to D for common ones

Hi Team,

I am a novice in excel and am trying to learn the ropes, however I need some help with the following situation.

I have 4 columns A, B, C & D. Now I need to compare A & C and for values common to A & C, I need copy their corresponding values in column B to D. Something as below where 4,6, 7, 8 & 9 are common to A & C and the values corresponding to these in B are populated in column D as well.

Roll nos. subject Roll nos. subject
1 Physics 4 biology
2 english 6 Math
3 chemistry 7 geography
4 biology 8 history
5 Computers 9 civics
6 Math 23
7 geography 34
8 history 35
9 civics 36
10 economincs 37



Please help me understand the logic as well so that I can refer to it and develop my own functions in future. Thanks in advance. PFA the same example in excel.

regards,

Pawan

I think in D2:

=VLOOKUP(C2,$A$2:$B$11,2,0)

copied down