Excel: Merge two tables based on one column

I have two Excel 2007 sheets A,B with the same columns.

B contains less rows, but has a column with updated data (i.e. data in this column is newer than in the same column in A). I want to take every row in B, find the corresponding row in A (through a unique key, f.e. column C1) and update the value of the column with the updated version from B.

Before

A           B   
C1 C2 C3    C1 C2 C3
1  2  3     1  2  99
2  6  7

After

A           B   
C1 C2 C3    C1 C2 C3
1  2  99    1  2  99
2  6  7

How could I achieve this?


You could use VLOOKUP to initially populate the data, then copy values onto a new sheet to remove the reference.