[英]MySQL Group Epoch Timestamp by Every 15 Minutes
我有一个数据库,它以相当高的频率收集一些数据并记录每个条目的时间戳(存储为纪元时间,而不是 mysql 日期时间)。 例如
timestamp rssi sender
-------------------------------------------
1592353967.171600 -67 9EDA3DBFFE15
1592353967.228000 -67 9EDA3DBFFE15
1592353967.282900 -62 E2ED2569BE2
1592353971.892600 -67 9EDA3DBFFE15
1592353973.962900 -61 2ADE2E4597B2
...
我的目标是能够在 15 分钟的时间间隔内获得所有行的计数,经过研究可以使用GROUP BY
获得。 理想情况下,最终的 output 看起来像这样
timestamp count
------------------------------
1592352000 (8:00pm EST) 38
1592352900 (8:15pm EST) 22
1592353800 (8:30pm EST) 0 <----- Important, must include periods with 0 entries
1592354700 (8:45pm EST) 61
...
我在这里主要遇到两件事:1.能够在结果中显示时间戳间隔2.在一个时间段内显示0行的间隔
我目前的尝试如下,它在正确的轨道上,因为那里的时间段内的数据实际上是正确的
Showing rows 0 - 23 (24 total, Query took 0.0264 seconds.)
SELECT count(*) AS total, MINUTE(FROM_UNIXTIME(timestamp)) AS minute
FROM requests
WHERE timestamp >= 1592352000 AND timestamp < (1592352000 + 3600)
GROUP BY MINUTE(FROM_UNIXTIME(timestamp))
total minute
55 32
89 33
64 34
55 35
87 36
82 37
90 38
69 39
74 40
47 41
89 42
53 43
71 44
87 45
72 46
83 47
86 48
83 49
113 50
76 51
77 52
88 53
81 54
28 55
这个数据是正确的,但是这里没有显示一些时间段(这个小时的前 30 分钟没有数据,因此第一minute
条目从 32 开始)。 还尝试通过使用每 15 分钟获取一次
SELECT count(*) AS total, MINUTE(FROM_UNIXTIME(timestamp)) AS minute
FROM requests
WHERE timestamp >= 1592352000 AND timestamp < (1592352000 + 3600)
GROUP BY MINUTE(FROM_UNIXTIME(timestamp)) DIV 15
#1055 - Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'wave_master.requests.timestamp' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by
任何帮助将不胜感激。
您可以使用“数字”表生成一小时内的 15 分钟周期 (0-3),然后将其LEFT JOIN
到您的计数中,按 15 分钟周期分组,使用COALESCE
将NULL
值替换为 0:
SELECT periods.period * 900 + 1592352000 AS timestamp,
FROM_UNIXTIME(periods.period * 900 + 1592352000) AS time,
COALESCE(counts.total, 0) AS total
FROM (
SELECT 0 period
UNION ALL SELECT 1
UNION ALL SELECT 2
UNION ALL SELECT 3
) periods
LEFT JOIN (
SELECT (timestamp - 1592352000) DIV 900 AS period,
COUNT(*) AS total
FROM requests
WHERE timestamp >= 1592352000 AND timestamp < 1592352000 + 3600
GROUP BY period
) counts ON counts.period = periods.period
Output (对于您问题中的数据以及其他几个值):
timestamp time total
1592352000 2020-06-17 00:00:00 1
1592352900 2020-06-17 00:15:00 1
1592353800 2020-06-17 00:30:00 5
1592354700 2020-06-17 00:45:00 0
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