У меня нет твоих столов, но это должно сработать
SELECT Citrix_ID, Wave,Document_Number, SUM(Attempt) as Incorrect, SUM(AttemptGreen) as Correct
, SUM(AttemptGreen) *100 / SUM(AttemptGreen) + SUM(Attempt) AS Percentage
,MIN((
SELECT SUM(T1.AttemptGreen) *100 / SUM(T1.AttemptGreen) + SUM(T1.Attempt)
FROM tblTrackQuestErrors T1
WHERE T1.Wave = tblTrackQuestErrors.Wave
AND T1.Document_Number = tblTrackQuestErrors.Document_Number
)) AS Percentage_Multi_CitrixID
FROM tblTrackQuestErrors
group by Citrix_ID,Wave,Document_Number