Class Average

You are given a table ‘Students’ which consists of the marks that students from different classes obtained in the final exam. Write an SQL query to find for each departments the number of students who managed to score above total average (average considering students of all classes) . The output should be sorted by ClassId .

NOTE : The output should contain one column by the name ‘A’ . 

Example :

NOTE: You only need to implement the given function. Do not read input, instead use the arguments to the function. Do not print the output, instead return values as specified. Still have a question? Checkout Sample Codes for more details.