12. Age Group - OK

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]'
        WHEN age BETWEEN 41 AND 50 THEN '[41-50]'
        WHEN age BETWEEN 51 AND 60 THEN '[51-60]'
        ELSE '[61+]'
    END AS age_group,
    COUNT(*) AS count
FROM
    wizard_deposits
GROUP BY
    age_group
ORDER BY
    age_group;