How do I generate a series of hourly averages in MySQL?

Question

I\'ve got data in ten minutes intervals in my table:

2009-01-26 00:00:00      12
2009-01-26 00:10:00      1.1
2009-01-26 00:20:00      11
2009-01-26 00:30:00         


        

Answer 1

It's unclear whether you want the average to be aggregated over days or not.

If you want a different average for midnight on the 26th vs midnight on the 27th, then modify Mabwi's query thus:

SELECT AVG( value ) , thetime
FROM hourly_averages
GROUP BY DATE( thetime ), HOUR( thetime )

Note the additional DATE() in the GROUP BY clause. Without this, the query would average together all of the data from 00:00 to 00:59 without regard to the date on which it happened.