Summarising rows

Hello Numbers Gurus,

I have a question that is, I am sure, easy...sorry.

I want to create a sheet with two tables: the first table has a number of rows and columns relating to business transactions (client name, units bought, value of units, total value, etc.). The second table will be a summary of the first.

So, let's say I have three clients, ABC Media, XYZ Design, and Bloggs Publishing. I summarise the income earned from each (in table or chart, to be honest).

How would I *automatically* retrieve the aggregate value of the highlighted cells to show either in a table or chart? I want a sort of search/if function that would aggregate any identical 'client' values—I could manually add the values together but that wouldn't very future proof...