题解 | 支付间隔平均值

select
    cast(
        avg(
            abs(timestampdiff(second, t1.logtime, t2.logtime))
        ) as signed
    ) as gap
from
    (
        select
            order_id,
            logtime
        from
            order_log
    ) t1
    join (
        select
            order_id,
            logtime
        from
            select_log
    ) t2 using (order_id)