题解 | 支付间隔平均值

# 两表取交集，两张表格共有的订单记录才值得计算
# CAST(... AS SIGHED)计算结果消除小数点和小数位
select
    CAST(avg(abs(timestampdiff(second,o.logtime,s.logtime))) AS SIGNED) as gap
from
    order_log o inner join select_log s
    on o.order_id = s.order_id
;