how to get sum of result from sql query

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SQL-Server-2008R2

DECLARE @dd TABLE (Username VARCHAR(250), WorkArea VARCHAR(50), Scope VARCHAR(50), Quality INT)
insert into @dd (Username ,WorkArea ,Scope ,Quality) select QAResource,WorkArea,ProjectScope ,quality from[PMT] .dbo.QADetailsnew 
insert into @dd (Username ,WorkArea ,Scope ,Quality)select a.resources,a.work_area,a.scope, a.Quality   from [workalloc] .[dbo] .work a

;WITH UserTotals AS
(
        -- initial values
 
	SELECT LEFT(Username, CHARINDEX(',', Username )-1) AS SingleUser, Quality, RIGHT(Username, LEN(Username) - CHARINDEX(',', Username)) AS Remainder
	FROM @dd
	WHERE CHARINDEX(',', Username)>0
	union all
	select Username as SingleUser,Quality, NULL as Remainder
	FROM @dd
	WHERE CHARINDEX(',',Username )=0
	
        -- here starts recursive part
	UNION ALL
	SELECT LEFT(Remainder, CHARINDEX(',', Remainder)-1) AS SingleUser, Quality, RIGHT(Remainder, LEN(Remainder) - CHARINDEX(',', Remainder)) AS Remainder
	FROM UserTotals 
	WHERE CHARINDEX(',', Remainder)>0
	UNION ALL
	SELECT Remainder AS SingleUser, Quality, NULL AS Remainder
	FROM UserTotals
	WHERE CHARINDEX(',', Remainder)=0
)
select distinct(SingleUser),(sum(Quality)/COUNT(SingleUser)) as QualityPercentage, 100-sum(Quality)/COUNT(SingleUser ) as ErrorPercentage
from UserTotals 

group by SingleUser  

SINGLEUSER    Quality%         Error%

John	        100		0
Robinson	100		0
Mary	        99		1
Rada		66		34
Anurag		55		45
Ashish		32		68
Denzil		98		2
Reena	        88		12
Martin		55		45
Robinson	94		6

I have two tables from different databases. First database is PMT in which i have named QADetailsnew Table.
In the second database is Workalloc and the table name is work.

In both of the tables i have the entry for the Username Robinson which gets executed twice because there is entry in the both the tables in different databases i need to get the sum of both. I have used the keyword distinct but it doesnt work in this case.