select
    user_ad_click_time.user_id uid
from
    user_ad_click_time
    left join user_payment_time on user_ad_click_time.user_id = user_payment_time.user_id
where
    date_add(click_time, interval 5 minute) > pay_time
    and user_ad_click_time.trace_id = user_payment_time.trace_id
order by
    user_ad_click_time.user_id desc

有坑，玛德。表连接时必须使用订单号，不然会返回两个用户id，因为其中一个用户的订单号在两张表中不一样(第二个表里多了个1)