MySQL in a Nutshell

Name

HOUR( )

Synopsis

HOUR(time)

This function returns the hour for the time given. For column types containing the time of day (e.g., DATETIME), the range of results will be from 0 to 23. For TIME datatype columns that contain data not restricted to day limits, this function may return values greater than 23.

SELECT HOUR(appointment)
FROM appointments
WHERE client_id = '3992'
   AND appointment > CURDATE( );
+-------------------+
| HOUR(appointment) |
+-------------------+
|                13 |
+-------------------+

This statement is selecting the upcoming appointment for a particular client. The hour is returned in military time (i.e., 13 is 1 p.m.).