Q:

Excel get relative cell value out of a search function result?

Is there a way to check if a text exists and is a unique entry within a column and then get a cells value which is relative to the position of the found cell? 
Here is the approach I tried and a more detailed explanation:
I am using this formula to check if a text exists and is a unique entry within the column D.
=COUNTIF(D:D;X1)=1

If that is the case this function returns TRUE.
Is there a way to get the cell's position, which is found by Excel to make the check for the function mentioned above? Moreover I am interested to know if then one can get a relative cell value from the position returned by Excel e.g: 2 columns on the left of the found position.
Do I need a different, maybe nested function or is this only possible with VBA?
What can I do?

A:

=MATCH(D1, X:X, 0) will find the row number of the first D1 in column X, or #N/A if there are none.
=INDEX(V:V, 42) will show the value of cell V42.
Combining this:
=IF(COUNTIF(X:X, D1)=1, INDEX(V:V, MATCH(D1, X:X, 0)), NA())
This should do what you need - if there's a unique match in column X, it shows the corresponding value from column V.
You can take this further by naming the columns, for example:
=IF(COUNTIF(client_email, D1)=1, INDEX(client_name, MATCH(D1, client_email, 0), NA())
This has the upside that you can see you're looking for the client's name if they and only they have a particular email address. And the downside that it's less obvious where on the sheet that data is stored. Swings and roundabouts!

