SQL 按年龄范围分组

SQL 按年龄范围分组的案例代码和解析

SELECT 
    CASE 
        WHEN age <= 20 THEN '0-20岁'
        WHEN age <= 30 THEN '21-30岁'
        WHEN age <= 40 THEN '31-40岁'
        WHEN age <= 50 THEN '41-50岁'
        ELSE '51岁以上'
    END AS age_group,
    COUNT(*) AS count
FROM 
    users
GROUP BY 
    age_group;