Provide the point of the winning margin in a match between Mumbai Indians and Royal Challengers Bangalore on May 28, 2008.
point of the winning margin refers to Win_Margin; Mumbai Indians refers to Team_Name = 'Mumbai Indians'; Royal Challengers Bangalore refers to Team_Name = 'Royal Challengers Bangalore'; on May 28 2008 refers to Match_Date = '2008-05-28'
SELECT T1.Win_Margin FROM Match AS T1 INNER JOIN Team AS T2 ON T2.Team_Id = T1.Team_1 INNER JOIN Team AS T3 ON T3.Team_Id = T1.Team_2 WHERE (T2.Team_Name = 'Mumbai Indians' AND T3.Team_Name = 'Royal Challengers Bangalore' AND T1.Match_Date = '2008-05-28') OR (T2.Team_Name = 'Royal Challengers Bangalore' AND T3.Team_Name = 'Mumbai Indians' AND T1.Match_Date = '2008-05-28')