SQL select unique items from everyone's desk

I have a SQL database: 3 desks, and what they contain
and I need to extract only the items that are unique on each desk and the desk the items are on.
The task looks disturbingly easy but my brain can’t comprehend the extra SQL commands, therefore I have 0 idea how I could get the answer for the question.

bing
database
exists
extract
go
ping
sql
task
uniq
unique

SELECT WhoseDesk, Item, count(Item) as found_nr 
FROM [Office] 
GROUP BY Item,WhoseDesk 
HAVING count(Item)=1 
ORDER BY found_nr, WhoseDesk,Item

Ty kind stranger for helping me out.

>Solution :

You can use this query for searching items that are on the desk and not on the other desk:

select *
from [Office] [outer]
where not exists( select 1 from [Office] 
                  where Item = [outer].Item
                  and WhoseDesk <> [outer].WhoseDesk )