要获取mysql的当前时区，你可以做以下事情:

 SELECT @@system_time_zone;   # from this you can get the system timezone 
 SELECT IF(@@session.time_zone = 'SYSTEM', @@system_time_zone, @@session.time_zone) # This will give you time zone if system timezone is different from global timezone

现在如果你想改变mysql时区，那么:

 SET GLOBAL time_zone = '+00:00';   # this will set mysql timezone in UTC
 SET @@session.time_zone = "+00:00";  # by this you can chnage the timezone only for your particular session 

Use LPAD(TIME_FORMAT(TIMEDIFF(NOW(), UTC_TIMESTAMP),’%H:%i’),6,’+') to get a value in MySQL's timezone format that you can conveniently use with CONVERT_TZ(). Note that the timezone offset you get is only valid at the moment in time where the expression is evaluated since the offset may change over time if you have daylight savings time. Yet the expression is useful together with NOW() to store the offset with the local time, which disambiguates what NOW() yields. (In DST timezones, NOW() jumps back one hour once a year, thus has some duplicate values for distinct points in time).

查看MySQL服务器时区支持和system_time_zone系统变量。这有用吗?

参考手册(第9.6节):

全局时区和客户端特定时区的当前值可以像这样检索: mysql> SELECT @@global。time_zone @@session.time_zone;

Edit The above returns SYSTEM if MySQL is set to use the system's timezone, which is less than helpful. Since you're using PHP, if the answer from MySQL is SYSTEM, you can then ask the system what timezone it's using via date_default_timezone_get. (Of course, as VolkerK pointed out, PHP may be running on a different server, but as assumptions go, assuming the web server and the DB server it's talking to are set to [if not actually in] the same timezone isn't a huge leap.) But beware that (as with MySQL), you can set the timezone that PHP uses (date_default_timezone_set), which means it may report a different value than the OS is using. If you're in control of the PHP code, you should know whether you're doing that and be okay.

但是MySQL服务器使用的时区可能是一个切题的问题，因为询问服务器它在哪个时区完全不能告诉您数据库中的数据。阅读以下细节:

进一步讨论:

如果您可以控制服务器，当然可以确保时区是已知的。如果你不能控制服务器，你可以像这样设置你的连接所使用的时区:

set time_zone = '+00:00';

这将时区设置为GMT，因此任何进一步的操作(如now())都将使用GMT。

注意，在MySQL中，时间和日期值不存储在时区信息中:

mysql> create table foo (tstamp datetime) Engine=MyISAM;
Query OK, 0 rows affected (0.06 sec)

mysql> insert into foo (tstamp) values (now());
Query OK, 1 row affected (0.00 sec)

mysql> set time_zone = '+01:00';
Query OK, 0 rows affected (0.00 sec)

mysql> select tstamp from foo;
+---------------------+
| tstamp              |
+---------------------+
| 2010-05-29 08:31:59 |
+---------------------+
1 row in set (0.00 sec)

mysql> set time_zone = '+02:00';
Query OK, 0 rows affected (0.00 sec)

mysql> select tstamp from foo;
+---------------------+
| tstamp              |
+---------------------+
| 2010-05-29 08:31:59 |      <== Note, no change!
+---------------------+
1 row in set (0.00 sec)

mysql> select now();
+---------------------+
| now()               |
+---------------------+
| 2010-05-29 10:32:32 |
+---------------------+
1 row in set (0.00 sec)

mysql> set time_zone = '+00:00';
Query OK, 0 rows affected (0.00 sec)

mysql> select now();
+---------------------+
| now()               |
+---------------------+
| 2010-05-29 08:32:38 |      <== Note, it changed!
+---------------------+
1 row in set (0.00 sec)

So knowing the timezone of the server is only important in terms of functions that get the time right now, such as now(), unix_timestamp(), etc.; it doesn't tell you anything about what timezone the dates in the database data are using. You might choose to assume they were written using the server's timezone, but that assumption may well be flawed. To know the timezone of any dates or times stored in the data, you have to ensure that they're stored with timezone information or (as I do) ensure they're always in GMT.

Why is assuming the data was written using the server's timezone flawed? Well, for one thing, the data may have been written using a connection that set a different timezone. The database may have been moved from one server to another, where the servers were in different timezones (I ran into that when I inherited a database that had moved from Texas to California). But even if the data is written on the server, with its current time zone, it's still ambiguous. Last year, in the United States, Daylight Savings Time was turned off at 2:00 a.m. on November 1st. Suppose my server is in California using the Pacific timezone and I have the value 2009-11-01 01:30:00 in the database. When was it? Was that 1:30 a.m. November 1st PDT, or 1:30 a.m. November 1st PST (an hour later)? You have absolutely no way of knowing. Moral: Always store dates/times in GMT (which doesn't do DST) and convert to the desired timezone as/when necessary.

要获取mysql的当前时区，你可以做以下事情:

 SELECT @@system_time_zone;   # from this you can get the system timezone 
 SELECT IF(@@session.time_zone = 'SYSTEM', @@system_time_zone, @@session.time_zone) # This will give you time zone if system timezone is different from global timezone

现在如果你想改变mysql时区，那么:

 SET GLOBAL time_zone = '+00:00';   # this will set mysql timezone in UTC
 SET @@session.time_zone = "+00:00";  # by this you can chnage the timezone only for your particular session 

下面的查询返回当前会话的时区。

select timediff(now(),convert_tz(now(),@@session.time_zone,'+00:00'));