mysql 分数段

-- 等分段，每10分为一段
SELECT 
    FLOOR(score / 10) * 10 AS score_range, 
    COUNT(*) AS student_count
FROM 
    students
GROUP BY 
    score_range;

-- 使用整数运算避免浮点数精度问题
SELECT 
    FLOOR(score / 10) * 10 AS score_range, 
    COUNT(*) AS student_count
FROM 
    students
GROUP BY 
    score_range;

-- 使用BETWEEN操作符确保范围不重叠
SELECT 
    CASE 
        WHEN score BETWEEN 0 AND 59 THEN '0-59'
        WHEN score BETWEEN 60 AND 69 THEN '60-69'
        WHEN score BETWEEN 70 AND 79 THEN '70-79'
        WHEN score BETWEEN 80 AND 89 THEN '80-89'
        ELSE '90-100'
    END AS score_range, 
    COUNT(*) AS student_count
FROM 
    students
GROUP BY 
    score_range;