Question

我试图在行之间找时间差异。我试过了，但它没有用。

SELECT id,locationDate,
  TIMESTAMPDIFF(SECOND,
    (SELECT MAX(locationDate) FROM location WHERE locationDate< t.locationDate),
    created_at
  ) as secdiff
FROM location t where tagCode = 24414 AND locationDate >= '2017-05-10 16:00:01' and locationDate <= '2017-05-10 16:59:59';

如何计算行间的时差？

您可以从sqlfiddle

获取样本结构和数据

Answer 1

我猜你只想要一个相关的子查询：

select l.id, l.locationDate,
       TIMESTAMPDIFF(SECOND,
                     (SELECT MAX(l2.locationDate)
                      FROM location l2
                      WHERE l2.locationDate < l.locationDate AND
                            l2.tagCode = l.tagCode
                     ),
                     locationDate
                    ) as secdiff
from location l
where l.tagCode = 24414 and
      l.locationDate > '2017-05-10 16:00:00' and
      l.locationDate < '2017-05-10 17:00:00';

我将日期/时间常数修改为更合理（从我的角度来看）。如果您真的关心一段时间之前或之后的一秒钟，那么您可以使用原始配方。

MySQL，如何获得行之间的时差

1 个答案: