Average of Subjects

CREATE OR REPLACE FUNCTION calculate_grade(
    subject1 INTEGER, subject2 INTEGER, subject3 INTEGER, 
    subject4 INTEGER, subject5 INTEGER, subject6 INTEGER
)
RETURNS TEXT AS $$
DECLARE
    total INTEGER;
    average DECIMAL;
    grade CHAR;
BEGIN
    -- Calculate total marks
    total := subject1 + subject2 + subject3 + subject4 + subject5 + subject6;

    -- Calculate average marks
    average := total / 6.0;

    -- Determine the grade based on average
    IF average >= 90 THEN
        grade := 'A';
    ELSIF average >= 80 THEN
        grade := 'B';
    ELSIF average >= 70 THEN
        grade := 'C';
    ELSIF average >= 60 THEN
        grade := 'D';
    ELSE
        grade := 'F';
    END IF;

    -- Return the grade
    RETURN grade;
END $$ LANGUAGE plpgsql;