好的，我不知道如何解释这个问题，这是我的第一篇文章。我是MySQL的相对noobie，过去两周的搜索让我这么远。现在我被卡住了。
我有一张桌子，包含大约120个不同方面的电力和温度场。此表每分钟插入一条新记录（每天1440条记录）。其中一个字段是时间戳。
一个字段在不常见且不可预测的基础上更新（抄表） 我想结合这里包含的两个查询的特征（第一个按天返回kWh，第二个返回仪表读数和仪表读数的日期时间）以返回仪表读数之间测量的总kWh。
我似乎无法弄清楚两件事：
如何执行使用动态日期作为间隔的“分组依据”语句？
如何从每个仪表读取并实际利用日期时间并将其解析为“datetime from”和“datetime to”以向第二个查询提供动态日期时间间隔（我假设我需要查询和子在这里查询）。
也许这些例子有助于解释：
SELECT DATE(`datetime`),
SUM(powerdata2.CH1WATT)/1000 / 60 +
SUM(powerdata2.CH2WATT)/1000 / 60 +
SUM(powerdata2.CH3WATT) /1000/ 60 +
SUM(powerdata2.CH4WATT)/1000/ 60 +
SUM(powerdata2.CH5WATT)/1000 / 60 +
SUM(powerdata2.CH6WATT)/1000 / 60 +
SUM(powerdata2.CH7WATT)/1000/ 60 +
SUM(powerdata2.CH8WATT)/1000/ 60 +
SUM(powerdata2.CH9WATT)/1000/ 60 +
SUM(powerdata2.CH10WATT)/1000/ 60 +
SUM(powerdata2.CH11WATT)/1000/ 60 +
SUM(powerdata2.CH12WATT)/1000/ 60 +
SUM(powerdata2.CH13WATT)/1000/ 60 +
SUM(powerdata2.CH14WATT)/1000/ 60 +
SUM(powerdata2.CH15WATT)/1000/ 60 +
SUM(powerdata2.CH16WATT)/1000/ 60 +
SUM(powerdata2.CH17WATT)/1000/ 60 +
SUM(powerdata2.CH18WATT)/1000/ 60 +
SUM(powerdata2.CH19WATT)/1000/ 60 +
SUM(powerdata2.CH20WATT)/1000/ 60 +
SUM(powerdata2.CH21WATT)/1000/ 60 +
SUM(powerdata2.CH22WATT)/1000/ 60 +
SUM(powerdata2.CH23WATT)/1000/ 60 +
SUM(powerdata2.CH24WATT)/1000/ 60 +
SUM(powerdata2.CH25WATT)/1000/ 60 +
SUM(powerdata2.CH26WATT)/1000/ 60 +
SUM(powerdata2.CH27WATT)/1000/ 60 +
SUM(powerdata2.CH28WATT)/1000/ 60 +
SUM(powerdata2.CH29WATT)/1000/ 60 +
SUM(powerdata2.CH30WATT)/1000/ 60 +
SUM(powerdata2.CH31WATT)/1000/ 60 +
SUM(powerdata2.CH32WATT)/1000/ 60 AS BYLOADTOTAL,
SUM(powerdata2.CH33WATT)/1000/ 60 +
SUM(powerdata2.CH34WATT)/1000/ 60 AS BYLINETOTAL
FROM db_pdata.powerdata2 powerdata2
GROUP BY DATE(`datetime`)
DATE(`datetime`) BYLOADTOTAL BYLINETOTAL
11/16/2014 12:00:00 AM 83.525883462254 91.148740563456
11/17/2014 12:00:00 AM 70.079734716742 76.287172546895
11/18/2014 12:00:00 AM 73.810085604727 79.983184481812
11/19/2014 12:00:00 AM 74.147556015524 80.981706193542
查询＃2：
SELECT powerdata2.`datetime`, powerdata2.MeterReading
FROM db_pdata.powerdata2 powerdata2
WHERE powerdata2.MeterReading <> 0
GROUP BY powerdata2.MeterReading
datetime MeterReading
11/16/2014 11:15:42 AM 31665
11/17/2014 8:08:59 PM 31774
11/18/2014 8:56:36 PM 31845
11/19/2014 6:19:36 PM 31919
以下查询显示表的整个数据结构：
SELECT powerdata2.*
FROM db_pdata.powerdata2 powerdata2
LIMIT 10
datetime MeterReading Frequency LINEVOLTS CH1AMP CH1WATT CH1VA CH2AMP CH2WATT CH2VA CH3AMP CH3WATT CH3VA CH4VA CH4AMP CH4WATT CH5AMP CH5WATT CH5VA CH6AMP CH6WATT CH6VA CH7AMP CH7WATT CH7VA CH8AMP CH8WATT CH8VA CH9AMP CH9WATT CH9VA CH10AMP CH10WATT CH10VA CH11AMP CH11WATT CH11VA CH12VA CH12AMP CH12WATT CH13AMP CH13WATT CH13VA CH14AMP CH14WATT CH14VA CH15AMP CH15WATT CH15VA CH16AMP CH16WATT CH16VA CH17AMP CH17WATT CH17VA CH18AMP CH18WATT CH18VA CH19AMP CH19WATT CH19VA CH20AMP CH20WATT CH20VA CH21AMP CH21WATT CH21VA CH22AMP CH22WATT CH22VA CH23AMP CH23WATT CH23VA CH24AMP CH24WATT CH24VA CH25AMP CH25WATT CH25VA CH26AMP CH26WATT CH26VA CH27AMP CH27WATT CH27VA CH28AMP CH28WATT CH28VA CH29AMP CH29WATT CH29VA CH30AMP CH30WATT CH30VA CH31AMP CH31WATT CH31VA CH32AMP CH32WATT CH32VA CH33AMP CH33WATT CH33VA CH34AMP CH34WATT CH34VA Temp1 Temp2 Temp3 Temp4
11/16/2014 12:59:57 AM 0 59.9975 120.1 0 0 0 0 0 0 2.887 318.3 349.1 93.24 0.7727 66.8 2.042 238.7 245.2 0.982 81.06 118.7 0 0 0 9.78 974.8 1173 0 0 0 0.2342 23.43 28.17 4.939 1160 1193 54.53 1.942 173.9 5 510.2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.1943 14.35 23.33 0.4549 53.92 0 0 0 0 0 0 0 0 0 0 21.11 2472 2531 12.2 1419 1466
11/16/2014 1:00:42 AM 0 59.9975 120.495 0 0 0 0 0 0 2.82424 303.538 340.824 95.1209 0.788176 69.2719 2.04481 239.852 246.324 1.01697 85.4419 122.629 0 0 0 1.11283 109.571 133.478 0 0 0 0.246643 24.5752 29.7424 5.172 1210.29 1247.76 54.7643 1.59219 148.538 4.95662 505.867 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0055619 0.613333 0.669524 0.185081 15.6624 22.3086 0.454357 54.1752 0 0 0 0 0 0 0 0 0 0 12.6476 1487.81 1525.05 12.2433 1432.24 1476
11/16/2014 1:01:42 AM 0 59.9965 120.56 0 0 0 0 0 0 2.81705 303.66 340.035 92.0565 0.762805 67.109 2.0443 239.825 246.2 1.02508 85.6915 123.46 0.003385 0.3083 0.40885 0.204645 18.7815 24.6745 0 0 0 0.24485 24.357 29.542 5.2875 1232.8 1273.55 54.726 1.13945 114.38 5.14215 529.75 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.01213 1.34 1.464 0.18982 16.088 22.89 0.453995 54.105 0 0 0 0 0 0 0 0 0 0 11.9675 1415.35 1444.15 12.5765 1467.55 1517.15
11/16/2014 1:02:42 AM 0 60.0238 120.581 0 0 0 0 0 0 2.8039 299.705 338.276 93.9919 0.778495 68.4267 2.04248 239.957 246.262 1.0139 84.7433 122.2 0 0 0 2.03708 203.555 245.21 0 0 0 0.245352 24.3976 29.591 5.39748 1261.48 1300.86 54.5971 1.11214 113.424 5.33819 558.21 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0218048 2.37286 2.63619 0.185895 15.5419 22.4381 0.452962 53.9957 0 0 0 0 0 0 0 0 0 0 13.2929 1566.9 1601.19 12.9143 1505.24 1558.05
11/16/2014 1:03:42 AM 0 60.0927 120.66 0 0 0 0 0 0 2.84455 302.485 343.03 92.8405 0.76965 66.9745 2.0453 240.535 246.835 1.00861 84.7535 121.66 0 0 0 0.20344 18.742 24.536 0 0 0 0.24779 24.842 29.9135 5.3822 1261.2 1298.45 54.701 1.14695 115.275 5.33315 556.775 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.01747 1.8975 2.111 0.187335 16.171 22.6255 0.453605 54.1005 0 0 0 0 0 0 0 0 0 0 12.0315 1422.5 1451.05 12.8825 1504.9 1555.5
11/16/2014 1:04:42 AM 0 60.0518 120.671 0 0 0 0 0 0 2.798 298.557 337.976 92.8676 0.768733 67.1881 2.0439 240.195 246.743 1.02934 86.6429 124.271 0 0 0 0.204162 18.8095 24.6671 0 0 0 0.246281 24.5333 29.7543 5.29024 1236.67 1277.9 54.9748 1.13286 114.6 5.30814 555.69 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0123143 1.37524 1.49048 0.189557 16.0786 22.8952 0.455343 54.3838 0 0 0 0 0 0 0 0 0 0 11.9071 1409.24 1438.71 12.7562 1487.57 1540.1
11/16/2014 1:05:42 AM 0 60.0268 120.63 0 0 0 0 0 0 2.82135 302.145 340.595 92.497 0.766315 66.8505 2.0428 240.36 246.71 1.02587 86.241 123.79 0.006635 0.6339 0.80335 0.460515 49.147 55.6065 0 0 0 0.244355 24.314 29.491 5.0421 1176.2 1216.85 54.6975 1.1284 114 5.12105 529.675 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.005605 0.597 0.674 0.187055 15.8315 22.587 0.45323 54.092 0 0 0 0 0 0 0 0 0 0 11.989 1419.25 1447.8 12.243 1432.4 1477.75
11/16/2014 1:08:15 AM 0 59.9694 120.291 0 0 0 0 0 0 2.82627 296.709 339.182 92.3236 0.765864 66.9227 2.03591 239.173 245.282 1.04531 87.4973 125.791 0 0 0 1.12709 127.345 135.664 0 0 0 0.247509 24.42 29.7845 4.75882 1102.64 1144.55 54.4818 2.08109 183.764 4.87545 494.482 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0108273 1.13727 1.29636 0.189227 16.6055 22.7927 0.452664 53.78 0 0 0 0 0 0 0 0 0 0 13.0745 1535.18 1572.18 11.6382 1359.27 1400.64
11/16/2014 1:09:15 AM 0 59.9694 119.987 0 0 0 0 0 0 2.816 295.713 338.393 92.6993 0.771933 66.5873 2.0314 238.267 244.28 1.04151 86.9147 125.127 0 0 0 1.12573 127.027 135.42 0 0 0 0.247393 24.438 29.7687 4.93753 1147.73 1187.93 54.2427 2.08 183.833 4.86893 494.36 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.185 15.802 22.2093 0.45134 53.5273 0 0 0 0 0 0 0 0 0 0 13.196 1548.87 1585.93 11.766 1369.2 1412.47
11/16/2014 1:11:42 AM 0 59.9902 120.533 0 0 0 0 0 0 2.87327 309.427 346.127 92.2993 0.766307 66.8533 2.03687 239.433 245.633 1.01329 84.8533 122.107 0 0 0 1.11633 126.267 134.68 0 0 0 0.2454 24.4787 29.5713 5.14507 1205.67 1241.67 54.3293 2.04667 182.04 4.87827 495.713 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.180413 15.566 21.7293 0.450887 53.7473 0 0 0 0 0 0 0 0 0 0 13.4787 1586.67 1623.13 12.0447 1407.93 1452.73