CREATE PROCEDURE proc2(IN student_id INT,IN course_id INT)
BEGIN
DECLARE score_value DECIMAL(5,2);
SELECT score INTO score_value
FORM scores
WHERE student_id=studentID AND course_id=courseId;
CASE
WHEN score_value >=90 THEN
SELECT '优';
WHEN score_value >=80 AND score_value<90 THEN
SELECT'良';
WHEN score_value>=70 AND score_value<80 THEN
SELECT'中';
WHEN score_value>=60 AND score_value<70 THEN
SELECT'及格';
ELSE
SELECT'不及格';
END CASE;
END $$;