CTE or Partition on group by ?

Hi

I have the following query

SELECT
      Count(DeviceId) as DeviceCount
      ,b.RootResellerId
      
  FROM Anayltics_Billing_DevicesReporting  b
  where DeviceId not in (863286020087590,869606020199992,869606020199993)
	and ReadingDate between '2020-01-10'  and '2020-01-31'
	Group by 	b.RootResellerId 

	order by DeviceCount desc

Select all Open in new window

this outputs results like this:

DeviceCount	RootResellerId
3673	3071
2303	3449
1533	2990
1153	2975
1068	2299

Select all Open in new window

I know need to do a join on
tblReseller.ResellerId = b.RootResellerId
to display tblReseller.ResellerName
This will enable me to see the reseller name on each row

However the inner join fails, i've read i may need to use CTE or partition but not sure how you add this to the end of the query.

sql server 2017