join two tables by score range from another table

I have two tables grade scale and result

I am triying to join the two in a query, but i get double records

Grade scale table example
id  min    max    grade
1   0     39      F
2   40    59      p
3   60    69      c
4   70    79      B
5   80    100     A 
...

And the result table

Result
Subjectid Total
1           69
2           53
''''

The expected output

subjectid total  grade
1          69    c
2          53    p
...

SELECT r.*
  FROM ResultView r
       LEFT JOIN GradeScale g
              ON ( r.total >= g.min AND r.total <= g.max ) 
 WHERE r.SessionID = 4 AND r.TermID = 1 AND r.ClassID = 9
 ORDER BY grade ASC;

but i'm not getting the expected output