Mysql 从一个带有时间戳的表中获取最大值，再从另一个表中获取一段时间内的3秒

当hopper2_设定点_满足表值为1时，我需要用TimeStr值显示EndTime，当设定点满足表值为1时，我需要从TimeStr+3秒开始，以hopper2_liveweight表的最大值显示权重

期望结果示例

数据和我的尝试 您可以从本文中访问这些数据，我在这里构建了模式并插入了数据的一小部分，或者如果您想用它在自己的MySQL数据库表上创建数据，那么这里也有相应的SQL

CREATE TABLE `hopper2_setpoint_met` (
  `TimeStr` datetime NOT NULL,
  `Value` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `hopper2_setpoint_met` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:02:33',1);
INSERT INTO `hopper2_setpoint_met` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:03:51',0);
INSERT INTO `hopper2_setpoint_met` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:45',1);
INSERT INTO `hopper2_setpoint_met` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:05:56',0);
INSERT INTO `hopper2_setpoint_met` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:49',1);

CREATE TABLE `hopper2_liveweight` (
  `TimeStr` datetime NOT NULL,
  `Value` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:02:33',292);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:02:34',298);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:02:35',300);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:02:36',300);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:14',106);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:15',111);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:16',116);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:17',123);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:19',132);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:20',142);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:21',148);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:22',154);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:23',160);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:24',166);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:25',172);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:26',177);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:27',184);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:29',190);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:30',195);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:31',201);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:32',208);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:33',213);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:34',220);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:35',226);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:36',232);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:37',239);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:38',244);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:39',251);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:40',257);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:41',263);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:42',269);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:43',276);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:44',282);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:45',288);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:46',293);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:47',299);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:04:48',299);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:18',108);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:19',112);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:20',117);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:21',123);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:22',128);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:23',135);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:24',141);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:25',148);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:26',154);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:27',160);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:28',165);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:29',172);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:30',177);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:31',183);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:32',190);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:33',196);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:34',201);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:35',208);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:36',213);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:37',220);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:38',226);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:39',231);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:40',237);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:41',242);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:42',248);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:43',254);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:44',262);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:45',269);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:46',276);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:47',282);
INSERT INTO `hopper2_liveweight` (`TimeStr`,`Value`) VALUES ('2019-06-30 12:06:49',288);

我昨天发布了一篇关于运输车类似问题的帖子，但我了解到使用临时表并不是最好的解决方案，尽管我在那里得到的答案确实给了我期望的结果

我还从收到的这些答案中学到了一些东西，并尝试了这些东西的几种变体，例如IfCASTValue为UNSIGNED！=对于我的新任务，0、值、空权重技巧和其他一些东西，我再次遇到了获得预期结果的困难

如果我将数据放入临时表中，我当然可以得到预期的结果，但它的性能不好，而且我相信这也会使过程变得过于复杂，实际上并不需要

我尝试了一些不同的变体，使用JOIN语句和UNION数据以及子查询，但在尝试获取timestr+3秒记录之间的最大权重时，出现了不足

我很想从一个有助于解决这个问题的答案中学到一些新的东西，一个灯泡在我的脑海中熄灭。因此，向前看，这是一个应用类似逻辑的问题，而不需要创建临时或永久临时表

---

如果需要的话，用一些JOIN语句甚至几个子查询将所有内容都保存在一个查询中，这对我很有用。我不确定使用MySQL会话变量是否有帮助，但我甚至尝试了一些方法，但都失败了

一个适合的查询是：

SELECT sm.TimeStr AS EndTime, Max(lw.Value) AS Weight
FROM (SELECT TimeStr FROM hopper2_setpoint_met WHERE Value = 1) sm
INNER JOIN hopper2_liveweight lw ON (sm.TimeStr + INTERVAL 3 SECOND) = lw.TimeStr
GROUP BY sm.TimeStr
;

---

让我知道我可以提供什么进一步的澄清，等等。是否不可能简化您的问题？例如，不必知道什么是传感器和hoppers@JaimeDrq是的，绝对有可能。这是一个该死的如果你做或该死的如果你不做的事情。我只是想给它添加一些上下文，但我希望通过数据、SQLFiddle、SQL、屏幕截图和其他一些文章中的噪音，人们可以从数据的技术方面看到我正在尝试做什么以及为什么。我也在粘贴中发布了SQL，并更改了表名，以发现我在粘贴过程中弄糟了一些东西，有些东西是无效的，因此从我发布此类问题的经验来看，从这个角度来看，似乎最好保持所有SQL的原样。这对我来说是可行的。我将设置触发器或计划事件，以便根据一个表中的每个记录更新运行一次，或者对于具有某种故障保护逻辑的计划事件，可能每15秒运行一次，并设置一个每小时和24小时的运行作业，以便根据此查询将记录插入到新表中。我认为这将是最好的表现，但这种逻辑给了我确切的结果，我需要。我想加入日期，然后加上+3秒，我只是因为某些原因而挣扎。我感谢你对这项任务的帮助。

SELECT sm.TimeStr AS EndTime, Max(lw.Value) AS Weight
FROM (SELECT TimeStr FROM hopper2_setpoint_met WHERE Value = 1) sm
INNER JOIN hopper2_liveweight lw ON (sm.TimeStr + INTERVAL 3 SECOND) = lw.TimeStr
GROUP BY sm.TimeStr
;