I have a database with a Datetime column containing intervals of +/- 30 seconds and a Value column containing random numbers between 10 and 100. My table looks like this:
datetime value
----------------------------
2016-05-04 20:47:20 12
2016-05-04 20:47:40 44
2016-05-04 20:48:30 56
2016-05-04 20:48:40 25
2016-05-04 20:49:30 92
2016-05-04 20:49:40 61
2016-05-04 20:50:00 79
2016-05-04 20:51:20 76
2016-05-04 20:51:30 10
2016-05-04 20:51:40 47
2016-05-04 20:52:40 23
2016-05-04 20:54:00 40
2016-05-04 20:54:10 18
2016-05-04 20:54:50 12
2016-05-04 20:56:00 55
What I want the following output:
datetime max_val min_val
-----------------------------------------
2016-05-04 20:45:00 92 12
2016-05-04 20:50:00 79 10
2016-05-04 20:55:00 55 55
Before I can even continue getting the maximum value and the minimum value, I first have to GROUP the datetime column into 5 minute intervals. According to my research I came up with this:
SELECT
time,
value
FROM random_number_minute
GROUP BY
UNIX_TIMESTAMP(time) DIV 300
Which actually GROUPS the datetime column into 5 minute intervals like this:
datetime
-------------------
2016-05-04 20:47:20
2016-05-04 20:50:00
2016-05-04 20:56:00
This comes very close as it takes the next closest datetime to, in this case, 20:45:00
, 20:50:00
, etc. I would like to rounddown the datetime to the nearest 5 minutes regardless of the seconds , for instance if the minutes are:
minutes rounddown
--------------------
10 10
11 10
12 10
13 10
14 10
15 15
16 15
17 15
18 15
19 15
20 20
The time could be 14:59 and I would like to rounddown to 10:00 . I also tried using this after hours of research:
SELECT
time,
time_rounded =
dateadd(mi,(datepart(mi,dateadd(mi,1,time))/5)*5,dateadd(hh,datediff(hh,0,dateadd(mi,1,time)),0))
But sadly this did not work. I get this error:
Incorrect parameter count in the call to native function 'datediff'
I tried this too:
SELECT
time, CASE
WHEN DATEDIFF(second, DATEADD(second, DATEDIFF(second, 0, time_out) / 300 * 300, 0), time) >= 240
THEN DATEADD(second, (DATEDIFF(second, 0, time) / 300 * 300) + 300, 0)
ELSE DATEADD(second, DATEDIFF(second, 0, time) / 300 * 300, 0)
END
Returning the same error.
How can I do this? And after the datetime is grouped, how can I get the max and min value of the data grouping?
Use various date partition functions inside a GROUP BY.
Code:
SELECT from_unixtime(300 * round(unix_timestamp(r.datetime)/300)) AS 5datetime,
MAX(r.value) AS max_value,
MIN(r.value) As min_value,
(SELECT r.value FROM random_number_minute ra WHERE ra.datetime = r.datetime order by ra.datetime desc LIMIT 1) as first_val
FROM random_number_minute r
GROUP BY UNIX_TIMESTAMP(r.datetime) DIV 300
Output:
5datetime max_value min_value first_val
May, 04 2016 20:45:00 92 12 12
May, 04 2016 20:50:00 79 10 79
May, 04 2016 20:55:00 55 55 55
SQL Fiddle: http://sqlfiddle.com/#!9/e16b1/17/0
Sorry if I'm repeating another answer. I'll delete if I am..
SELECT FROM_UNIXTIME(FLOOR(UNIX_TIMESTAMP(datetime)/300)*300) x
, MIN(value) min_value
, MAX(value) max_value
FROM my_table
GROUP
BY x;
SELECT
timestamp(concat(date(time), ' ', hour(time), ':', minute(time) div 5 * 5)) as floor_time,
min(value),
max(value)
FROM random_number_minute
GROUP BY date(time), hour(time), minute(time) div 5 * 5
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