MySql - 计算多行的时间差

Question

我有一个包含制造装配数据的表，包括时间戳。我试图确定“作业”开始之间的平均间隔(以分钟为单位)。

返回 ID 和时间的查询如下所示:

select job_id, job_started from JobTable where job_started >= '2016-07-01' and job_started <= '2016-07-31';

我正在寻找每行之间的时间差的输出:

1518211413

Answer 1

获取平均间隔(以秒为单位):

select (to_seconds(max(job_started)) - to_seconds(min(job_started))) / (count(*) - 1) as average_interval_seconds
from JobTable
where date(job_started) >= '2016-07-01'
  and date(job_started) <= '2016-07-31'
;

获取所有间隔(以秒为单位):

select to_seconds((
  select t2.job_started
  from JobTable t2
  where t2.job_started > t1.job_started
    and date(t2.job_started) <= '2016-07-31'
  limit 1
)) - to_seconds(t1.job_started) as interval_seconds
from JobTable t1
where date(t1.job_started) >= '2016-07-01'
  and date(t1.job_started) <= '2016-07-31'
  and t1.job_started <> (
    select job_started
    from JobTable
    where date(job_started) <= '2016-07-31'
    order by job_started desc
    limit 1
  )
;

http://sqlfiddle.com/#!9/1f8dc3/2