I am trying to calculate the class average of a class where students can hold different amounts of subjects (e.g.: two students in a class of which one takes 3 subjects and the other 2). How do I get the class average that applies to all students? I already have their total term score in a table. I know the formula for calculating the average is simply the total averages of individual students divided by the number of students, but I can't seem to get it working. Can anyone please help me write a query that will calculate and print out this class average?
Here is what I have tried so far:
SELECT student_id, SUM(CA_total)/count(term_total) AS average FROM score_entry GROUP BY student_id
BUT I want the final result to be the sum of 25 + 26.5 which will be 51.5 then divided by the 2 students in the class should give 25.75. this is the class average. I want the query or code that will echo out the final answer 25.75. thanks THIS IS SAMPLE OF THE EXACT DATABASE