Question

我有一张名为＆＃34; powerpro＆＃34;包括＆＃34; power＆＃34;记录在当天每一分钟的数据如下:(假设包括一个月的记录）

+---------------------+---------------+---------------+---------------+
|      date_time      | phase_1_power | phase_2_power | phase_3_power |
+---------------------+---------------+---------------+---------------+
| 2014/12/01 00:00:00 | 73.0767       | -68.2627      | -73.0767      |
| 2014/12/01 00:01:00 | 73.0293       | -68.3134      | -73.0293      |
| 2014/12/01 00:02:00 | 72.9819       | -68.3641      | -72.9819      |
| 2014/12/01 00:03:00 | 72.9345       | -68.4148      | -72.9345      |
| 2014/12/01 00:04:00 | 72.8871       | -68.4655      | -72.8871      |
| 2014/12/02 00:00:00 | 72.8397       | -68.5162      | -72.8397      |
| 2014/12/02 00:01:00 | 72.7923       | -68.5669      | -72.7923      |
| 2014/12/02 00:02:00 | 72.7449       | -68.6176      | -72.7449      |
| 2014/12/02 00:03:00 | 72.6975       | -68.6683      | -72.6975      |
| 2014/12/02 00:04:00 | 72.6501       | -68.7119      | -72.6501      |
| 2014/12/03 00:00:00 | 72.6027       | -68.7697      | -72.6027      |
| 2014/12/03 00:01:00 | 72.5553       | -68.8204      | -72.5553      |
| 2014/12/03 00:02:00 | 72.5079       | -68.8711      | -72.5079      |
| 2014/12/03 00:03:00 | 72.4605       | -68.9218      | -72.4605      |
| 2014/12/03 00:04:00 | 72.4131       | -68.9725      | -72.4131      |
+---------------------+---------------+---------------+---------------+

我想得到平衡结束时间UNIX_TIMESTAMP（）value -start time UNIX_TIMESTAMP（）值AND 结束时间=开始时间UNIX_TIMESTAMP（）值+ UNIX_TIMESTAMP（）下一个第7个日期的值

我试过了：

SELECT UNIX_TIMESTAMP(a1.date_time) AS time_reff, a1.phase_1_power AS ph1,  a1.phase_2_power AS ph2,  a1.phase_3_power AS ph3
FROM powerpro a1

JOIN (SELECT UNIX_TIMESTAMP(date_time) time, MIN(UNIX_TIMESTAMP(date_time)) AS min 
        FROM powerpro
        GROUP BY  date_time
    )a2 ON a1.date_time = a2.min

JOIN (SELECT UNIX_TIMESTAMP(date_time) time, MIN(UNIX_TIMESTAMP(date_time)) AS min 
        FROM powerpro
        GROUP BY date_time
       ) a3 ON a1.date_time = a3.time - INTERVAL 7 DAY 

WHERE a1.date_time BETWEEN DATE_SUB(NOW(), INTERVAL 7 DAY) AND NOW() ORDER BY a1.date_time

但只有空洞的结果。

任何人都可以帮助我吗？感谢

Answer 1

删除WHERE部分：它会将结果集限制为仅在NOW()的7天内开始日期的条目。同时，由于JOIN s，您只输出一对开始时间 - 结束时间间隔为7天。结合起来，这意味着唯一可以输出的行是结束时间为NOW()且开始时间为DATE_SUB(NOW(), INTERVAL 7 DAY)的行。

当您删除WHERE部分时，您将获得所有开始时间 - 结束时间间隔为7天。

更新1：

由于这仍然不起作用，让我们尝试逐个重建此查询。

首先尝试这个：

SELECT UNIX_TIMESTAMP(date_time) time, MIN(UNIX_TIMESTAMP(date_time)) AS min 
        FROM powerpro
        GROUP BY DATE(date_time)

这应该是每天最早的时间戳。

更新2：

现在尝试：

SELECT UNIX_TIMESTAMP(a1.date_time) AS time_reff, a1.phase_1_power AS ph1,  a1.phase_2_power AS ph2,  a1.phase_3_power AS ph3
FROM powerpro a1

JOIN (SELECT UNIX_TIMESTAMP(date_time) time, MIN(UNIX_TIMESTAMP(date_time)) AS min 
        FROM powerpro
        GROUP BY DATE(date_time)
    )a2 ON time_reff = a2.min

这应该为每天的最早时间戳提供所有阶段。

更新3：

SELECT UNIX_TIMESTAMP(a1.date_time) AS time_reff, a1.phase_1_power AS ph1,  a1.phase_2_power AS ph2,  a1.phase_3_power AS ph3
FROM powerpro a1

JOIN (SELECT UNIX_TIMESTAMP(date_time) time, MIN(UNIX_TIMESTAMP(date_time)) AS min 
        FROM powerpro
        GROUP BY DATE(date_time)
    )a2 ON UNIX_TIMESTAMP(a1.date_time) = a2.min

JOIN (SELECT UNIX_TIMESTAMP(date_time) time, MIN(UNIX_TIMESTAMP(date_time)) AS min 
        FROM powerpro
        GROUP BY DATE(date_time)
    )a3 ON CAST(a1.date_time AS DATETIME) = DATE_SUB(a3.time, INTERVAL 1 DAY)

更新4：

SELECT UNIX_TIMESTAMP(a1.date_time) AS time_reff, a1.phase_1_power AS ph1,  a1.phase_2_power AS ph2,  a1.phase_3_power AS ph3
FROM powerpro a1
JOIN (SELECT UNIX_TIMESTAMP(date_time) time, MIN(UNIX_TIMESTAMP(date_time)) AS min 
        FROM powerpro
        GROUP BY DATE(date_time)
    )a2 ON UNIX_TIMESTAMP(a1.date_time) = a2.min
JOIN (SELECT UNIX_TIMESTAMP(date_time) time, MIN(UNIX_TIMESTAMP(date_time)) AS min 
        FROM powerpro
        GROUP BY DATE(date_time)
    )a3 ON UNIX_TIMESTAMP(a1.date_time) = a3.min - 86400

区分两个Unix_Timestamp引用

1 个答案: