KH_challenge-student_grades-2

CREATE TABLE student_grades (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT,
    number_grade INTEGER,
    fraction_completed REAL,
    percent_completed INTEGER);
    
INSERT INTO student_grades (name, number_grade, fraction_completed, percent_completed)
    VALUES ("Winston", 90, 0.805, 0);
    
INSERT INTO student_grades (name, number_grade, fraction_completed, percent_completed)
    VALUES ("Winnefer", 95, 0.901, 0);
    
INSERT INTO student_grades (name, number_grade, fraction_completed, percent_completed)
    VALUES ("Winsteen", 85, 0.906, 0);
    
INSERT INTO student_grades (name, number_grade, fraction_completed, percent_completed)
    VALUES ("Wincifer", 66, 0.7054, 0);
    
INSERT INTO student_grades (name, number_grade, fraction_completed, percent_completed)
    VALUES ("Winster", 76, 0.5013, 0);
    
INSERT INTO student_grades (name, number_grade, fraction_completed, percent_completed)
    VALUES ("Winstonia", 82, 0.9045, 0);


UPDATE student_grades SET percent_completed = round(fraction_completed * 100);


SELECT name, number_grade, percent_completed FROM student_grades;


SELECT
    COUNT(*),
    CASE 
        WHEN number_grade > 90 THEN "A"
        WHEN number_grade > 80 THEN "B"
        WHEN number_grade > 70 THEN "C"
        ELSE "F" 
        END as "letter_grade"
FROM student_grades
GROUP BY letter_grade;