MySQL GROUP BY date when using datetime

Question

In MySQL, let's say I have a table with a column called 'actionTime' declared as a 'datetime' (YYYY-MM-DD HH:MM:SS).

Is there an easy way to use "GROUP BY actionTime" but only use the 'date' part of the 'datetime'?

Thanks

Answer 1

Ahh Google .. so easy to use.
http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html#function_date

mysql> SELECT DATE('2003-12-31 01:02:03');
        -> '2003-12-31'

Answer 2

Yep, use MySQL's DATE() function:

SELECT * FROM your_table GROUP BY DATE(actionTime);

Answer 3

Should be able to

GROUP BY date(actionTime)

See this for more info.