GROUP BY interval overlapping timestamp MySQL query

问题

I've been reading other questions and had no luck. I have a table with columns (stamp,value). The 'stamp' column stores hourly timestamps. What I'm trying to do is to retrieve SUM(value) for intervals of 24 hours depending on a range of timestamps specified in the query:

SELECT stamp, 
       Sum(value) 
FROM   table 
WHERE  stamp >= Date_sub('2012-12-02 05:00:00', INTERVAL 1 day) 
       AND stamp < '2013-01-01 05:00:00' 
GROUP  BY Date(stamp)

The result I'm looking for would look like this:

stamp                      value
2012-12-02 05:00:00        12024
2012-12-03 05:00:00        11211
2012-12-04 05:00:00        19834
...
2013-01-01 05:00:00        10232

Actual table looks like this:

stamp                      value
2012-12-01 01:00:00        345
2012-12-01 02:00:00        100
2012-12-01 03:00:00        104
2012-12-01 04:00:00        103
2012-12-01 05:00:00        101
2012-12-01 06:00:00        102
...
2013-01-01 05:00:00        207
2013-01-01 06:00:00        307
2013-01-01 07:00:00        223
...

*Note that the stamp column's datatype is timestamp

回答1:

I think you just want to set the hours to 5, to be consistent with your range. If so, you can do this:

SELECT cast(date(stamp) as datetime) + interval 5 hour
       Sum(value) 
FROM   table 
WHERE  stamp >= Date_sub('2012-12-02 05:00:00', INTERVAL 1 day) 
       AND stamp < '2013-01-01 05:00:00' 
GROUP  BY Date(stamp)

But, I think you might actually want to phrase this a bit differently:

SELECT cast(date(stamp - interval 5 hour) as datetime) + interval 5 hour
       Sum(value) 
FROM   table 
WHERE  stamp >= Date_sub('2012-12-02 05:00:00', INTERVAL 1 day) 
       AND stamp < '2013-01-01 05:00:00' 
GROUP  BY Date(stamp - interval 5 hour)

This actually realigns the dates on the 5-hour boundary.

Note: these queries are untested, so may contain syntax errors.

This is assuming that the timestamp is really a datetime. If it is a UNIX timestamp, you need to convert it first.

来源：https://stackoverflow.com/questions/14487945/group-by-interval-overlapping-timestamp-mysql-query

标签

mysql

group-by

timestamp

intervals