题解 | 任意两个连续自然月练题次数大于1的用户

### 逻辑 先求出用户的答题次数 再将当月表跟次月表相连接 最后再筛选

WITH
    monthly_practice AS(
        SELECT 
            device_id,
            YEAR(event_date) year,
            MONTH(event_date) month,
            COUNT(question_id) practice_cnt
        FROM question_practice_detail
        GROUP BY YEAR(event_date),MONTH(event_date),device_id
    ),
    consecutive_month AS(
        SELECT
            t1.device_id,
            t1.practice_cnt,
            t2.practice_cnt practice_cnt2 
        FROM monthly_practice t1
        LEFT JOIN monthly_practice t2
        ON t1.device_id = t2.device_id
        WHERE (t1.year = t2.year AND t1.month+1 = t2.month)
        OR (t1.year+1 = t2.year AND t1.month=12 AND t2.month=1)
    )

SELECT DISTINCT device_id
FROM consecutive_month
WHERE practice_cnt+practice_cnt2 >1
order by device_id DESC