mysql 年龄分段

SELECT 
    CASE 
        WHEN age BETWEEN 0 AND 10 THEN '0-10'
        WHEN age BETWEEN 11 AND 20 THEN '11-20'
        WHEN age BETWEEN 21 AND 30 THEN '21-30'
        WHEN age BETWEEN 31 AND 40 THEN '31-40'
        ELSE '40+'
    END AS age_group,
    COUNT(*) AS count
FROM 
    users
GROUP BY 
    age_group;

SELECT 
    CASE 
        WHEN age >= 0 AND age <= 10 THEN '0-10'
        WHEN age >= 11 AND age <= 20 THEN '11-20'
        WHEN age >= 21 AND age <= 30 THEN '21-30'
        WHEN age >= 31 AND age <= 40 THEN '31-40'
        ELSE '40+'
    END AS age_group,
    COUNT(*) AS count
FROM 
    users
GROUP BY 
    age_group;

CREATE INDEX idx_age ON users(age);

SELECT 
    CASE 
        WHEN age >= 0 AND age <= 10 THEN '0-10'
        WHEN age >= 11 AND age <= 20 THEN '11-20'
        WHEN age >= 21 AND age <= 30 THEN '21-30'
        WHEN age >= 31 AND age <= 40 THEN '31-40'
        ELSE '40+'
    END AS age_group,
    COUNT(*) AS count
FROM 
    users
GROUP BY 
    age_group
LIMIT 10 OFFSET 0;