I am trying this. My field name was in fact mHour

select mhour, avg(mRating) as AvgRating from Ratings GROUP BY mhour

It's working. However the table has 700,000 + records in it, and the above gives me a table with 24 records,
with each hour having an average for that hour in the entire table. In point of fact, my Ratings table is really like this:

mYear     mMonth     mDate     mHour     mMin     mRating
2013	5	         5/9/2013	    16	1600	13.84
2013	5	         5/9/2013	    17	1615	13.44

And what I really need is a row-by-row description, for every single day, of the average hourly ratings?
Thank you so much,
Steve