match 2 databases based on a column with same values
 

I have 2 sets of data. one set has a column of values that identify the data,
the other columns are just data, the other data base is the same but with
different data. except some numbers are in one and not the other, and some
numbers are repeated. i need to match the data in the second database with
the data of the first database based on the identifying column.
if you don;t understand the question please ask - i could give an example