The docs are an excellent read.
CONVERT_TZ(dt,from_tz,to_tz)
CONVERT_TZ() converts a datetime value dt from the time zone given by from_tz to the time zone given by to_tz and returns the resulting value. Time zones are specified as described in Section 9.6, “MySQL Server Time Zone Support”. This function returns NULL if the arguments are invalid.
The current values of the global and client-specific time zones can be retrieved like this:
mysql> SELECT @@global.time_zone, @@session.time_zone;
The timezone values can be given in several formats, none of which are case sensitive:
- The value 'SYSTEM' indicates that the
time zone should be the same as the
system time zone.
- The value can be given as a string
indicating an offset from UTC, such
as '+10:00' or '-6:00'.
- The value can be given as a named
time zone, such as 'Europe/Helsinki',
'US/Eastern', or 'MET'. Named time
zones can be used only if the time
zone information tables in the mysql
database have been created and
populated.
PS: Read about GMT vs UTC on About.com. GMT is the solar time at Greenwich, London while UTC] is a time standard based on International Atomic Time (TAI) with leap seconds added at irregular intervals to compensate for the Earth's slowing rotation. Both are same if viewed as a time-zone.
