The system time zone. When the server starts, it attempts to determine the time zone of the host machine and uses it to set the system_time_zone system variable. The value does not change thereafter.

You can set the system time zone for MySQL Server at startup with the --timezone=timezone_name option to mysqld_safe. You can also set it by setting the TZ environment variable before you start mysqld. The permissible values for --timezone or TZ are system dependent. Consult your operating system documentation to see what values are acceptable.

The server's current time zone. The global time_zone system variable indicates the time zone the server currently is operating in. The initial value for time_zone is 'SYSTEM', which indicates that the server time zone is the same as the system time zone.

The initial global server time zone value can be specified explicitly at startup with the --default-time-zone=timezone option on the command line, or you can use the following line in an option file:

default-time-zone='timezone'

If you have the SUPER privilege, you can set the global server time zone value at runtime with this statement:

mysql> SET GLOBAL time_zone = timezone;

Per-connection time zones. Each client that connects has its own time zone setting, given by the session time_zone variable. Initially, the session variable takes its value from the global time_zone variable, but the client can change its own time zone with this statement:

mysql> SET time_zone = timezone;

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.

To load a single time zone file tz_file that corresponds to a time zone name tz_name, invoke mysql_tzinfo_to_sql like this:

shell> mysql_tzinfo_to_sql tz_file tz_name | mysql -u root mysql

With this approach, you must execute a separate command to load the time zone file for each named zone that the server needs to know about.

If your time zone needs to account for leap seconds, initialize the leap second information like this, where tz_file is the name of your time zone file:

shell> mysql_tzinfo_to_sql --leap tz_file | mysql -u root mysql

After running mysql_tzinfo_to_sql, it is best to restart the server so that it does not continue to use any previously cached time zone data.

To use a time zone package that contains SQL statements, download and unpack it, then load the package file contents into your existing time zone tables:

shell> mysql -u root mysql < file_name

Then restart the server.

To use a time zone package that contains .frm, .MYD, and .MYI files for the MyISAM time zone tables, download and unpack it. These table files are part of the mysql database, so you should place the files in the mysql subdirectory of your MySQL server's data directory. Stop the server before doing this and restart it afterward.