USE my_tutorial;
SELECT AVG(mark) FROM student where id<=6;
SELECT class, AVG(mark) as avg_mark FROM student WHERE id<=6 GROUP BY class;
SELECT AVG(mark) FROM student WHERE id IN ( 1,2,3,4);
SELECT * FROM student WHERE class='Six' and mark <(SELECT avg(mark) from student where class='Six');
SELECT class, AVG(mark) FROM student GROUP BY class HAVING AVG(mark) >75;
SELECT id, name, social, math, science,
(social+ math+science) as Total,
(social+ math+science)/3 as avg 
FROM student_sum;