CREATE TABLE student_grades (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT,
    number_grade INTEGER,
    fraction_completed REAL);
    
INSERT INTO student_grades (name, number_grade, fraction_completed)
    VALUES ("Winston", 90, 0.805);
INSERT INTO student_grades (name, number_grade, fraction_completed)
    VALUES ("Winnefer", 95, 0.901);
INSERT INTO student_grades (name, number_grade, fraction_completed)
    VALUES ("Winsteen", 85, 0.906);
INSERT INTO student_grades (name, number_grade, fraction_completed)
    VALUES ("Wincifer", 66, 0.7054);
INSERT INTO student_grades (name, number_grade, fraction_completed)
    VALUES ("Winster", 76, 0.5013);
INSERT INTO student_grades (name, number_grade, fraction_completed)
    VALUES ("Winstonia", 82, 0.9045);
SELECT name, number_grade, ROUND(fraction_completed * 100) AS 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;