How to set time zone of mysql?

There are 3 places where the timezone might be set in MySQL:

in the file "my.cnf" in the [mysqld] section

default-time-zone='+00:00'

@@global.time_zone variable

To see what value they are set to

SELECT @@global.time_zone;

To set a value for it use either one:

SET GLOBAL time_zone = '+8:00';
SET GLOBAL time_zone = 'Europe/Helsinki';
SET @@global.time_zone='+00:00';

(using named timezones like 'Europe/Helsinki' means that you have to have a timezone table properly populated)

@@session.time_zone variable

SELECT @@session.time_zone;

To set it use either one:

SET time_zone = 'Europe/Helsinki';
SET time_zone = "+00:00";
SET @@session.time_zone = "+00:00";

both might return SYSTEM which means that they use the timezone set in my.cnf. For timezone names to work you must setup your timezone information tables need to be populated:http://dev.mysql.com/doc/refman/5.1/en/time-zone-support.html I also mention how to populate those tables in this answer

To get the current timezone

SELECT TIMEDIFF(NOW(), UTC_TIMESTAMP);

It will return 02:00:00 if your timezone is +2:00.

To get the current UNIX timestamp:

SELECT UNIX_TIMESTAMP();
SELECT UNIX_TIMESTAMP(NOW());

To get the timestamp column as a UNIX timestamp

SELECT UNIX_TIMESTAMP(`timestamp`) FROM `table_name`

To get a UTC datetime column as a UNIX timestamp

SELECT UNIX_TIMESTAMP(CONVERT_TZ(`utc_datetime`, '+00:00', @@session.time_zone)) FROM `table_name`

Note: Changing the timezone will not change the stored datetime or timestamp, but it will show select a different datetime from timestamp columns