题解 | SQLW19 查询下订单用户访问次数？
WITH t1 AS (
SELECT *
FROM order_tb
WHERE DATE(order_time) = '2022-09-02'
),
t2 AS (
SELECT *
FROM visit_tb
WHERE DATE(visit_time)='2022-09-02'
AND user_id IN
(SELECT user_id FROM t1 GROUP BY user_id)
),
t3 AS (
SELECT user_id,
count(user_id) AS visit_nums
FROM t2
GROUP BY user_id
ORDER BY visit_nums DESC
)SELECT * FROM t3;
# 这道题的关键在于迷惑性，不需要考虑离开也是当天日期！
