i want to show the attendance of a student in percentage
I'm gonna assume couple of things here. For attendance column I'm gonna assume "Yes" if the student is present on that particular date, and "No" if otherwise.

SELECT f.name, f.subject, t2.attendance_percentage 
FROM fsignup f
JOIN (SELECT subject, Yes/SUM(Yes+No)*100 AS attendance_percentage FROM (SELECT subject, SUM(CASE WHEN attendance="Yes" THEN 1 ELSE 0) AS Yes, SUM(CASE WHEN attendance="No" THEN 1 ELSE 0) AS No FROM attendance GROUP BY subject)t1)t2
ON f.subject=t2.subject
GROUP BY f.name, f.subject