题解 | #某宝店铺连续2天及以上购物的用户及其对应的天数#

select 
    user_id,
    count(1)+1 as days_count --注意：若有三行记录 1&2、2&3、3&4，是连续4天购物
from(
    select
        user_id,
        sales_date,
        lag(sales_date) over (partition by user_id order by sales_date asc) as bf_day
    from 
        sales_tb) as t
where datediff(bf_day,sales_date) = -1 --保证日期是连续的
group by 1
order by user_id asc