Следующий запрос должен делать то, что вы хотите, решение для сервера SQL:
CREATE TABLE #temp (MR_ID INT, Sup_ID INT, [Status] VARCHAR(20))
INSERT INTO #temp VALUES
(1,1,'Rejected'),
(1,1,'Accepted'),
(1,1,'Accepted'),
(1,1,'Rejected'),
(2,2,'InProgress'),
(2,2,'InProgress'),
(2,2,'Accepted'),
(2,2,'Fordwarded')
SELECT t.MR_ID, t.Sup_ID, t.[Status], (COUNT(t.[Status]) * 100 / (SELECT COUNT(*) FROM #temp WHERE MR_ID = t.MR_ID AND Sup_ID = t.Sup_ID )) AS [Percentage]
FROM #temp t
GROUP BY MR_ID, Sup_ID, [Status]
Результат как ниже,
MR_ID Sup_ID Status Percentage
1 1 Accepted 50
1 1 Rejected 50
2 2 Accepted 25
2 2 Fordwarded 25
2 2 InProgress 50