HELP HELP HELP SQL CALCULATION

Question

Im really struggling with something and I desperately need help and advice on how to do this.
I have a SQL link table called student_monitor containing the follwing attributes and e.g. data
student_id, Class_id, Predicted_Grade, Actual_Grade
1 1 A C
2 1 B B
3 1 C B
I need to be able to flag which students are under achieving on their target grades and dont know how to do this or the best way to do this as i cannot calculate the diff between a char?
thanks for any help this is quite urgent so a quick response will be appreciated

Answer 1

Yes we can do that.
select * from student_monitor where predicted_grade > actual_grade;It should be predicted_grade < actual_grade as you see in the data, only the first student with student_id 1 is under acheived, as he is predicted to get A, but got C. So he under acheived
? (In fact in your statement it should also be > not <, since we want those who are under-achieving.)The answer is same as above.
see below:
SQL> with student_monitor as
  2  (select 1 student_id, 1 Class_id, 'A' Predicted_Grade, 'C' Actual_Grade  from dual union all
  3  select 2, 1, 'B', 'B' from dual union all
  4  select 3, 1, 'C', 'B' from dual )
  5  --
  6  select * from student_monitor
  7  where predicted_grade > actual_grade;
STUDENT_ID   CLASS_ID P A
         3          1 C BStudent_Id 3 was predicted to get C, but instead he got B, so he over acheived. Change > to <
SQL> with student_monitor as
  2  (select 1 student_id, 1 Class_id, 'A' Predicted_Grade, 'C' Actual_Grade  from dual union all
  3  select 2, 1, 'B', 'B' from dual union all
  4  select 3, 1, 'C', 'B' from dual )
  5  --
  6  select * from student_monitor
  7  where predicted_grade < actual_grade;
STUDENT_ID   CLASS_ID P A
         1          1 A C