题目仅要求返回第1、2次购买时间,故只需返回前两条记录,时间最小为第1次,时间最大为第2次,购买次数可用开窗函数计算,代码如下: select a.user_id, min(a.date) as first_buy_date, max(a.date) as second_buy_date, a.cnt from (select user_id, date, row_number() over(partition by user_id order by date) as rank_no, count(*) over(partition by...