MySQL - difference between CET and CEST

I need to move some tables from MySQL database to PostgreSQL. So i've checked, which time zone is MySQL server using by checking system variable:

system time zone    CET

CET - as far as i know - in contrast of CEST - is never more than UTC+1. CEST is in summer UTC+2. According to http://en.wikipedia.org/开发者_如何学编程wiki/Central_European_Time

But SELECT CURRENT_TIMESTAMP() actually returns CEST time (UTC+2):

Why?

So i've checked, which time zone is MySQL server using by checking system variable

How did you do this?

Try this query please and tell me the results:

SELECT @@global.time_zone, @@session.time_zone;

There can be three types of results.

• SYSTEM

which means, that MySQL uses the timezone settings of your OS

• something like '+01:00' or whatever value

which is the difference to the UTC (Coordinated Universal Time)

• something like 'Europe/Berlin'

which is basically the same as above, but you have populated your timezone tables in MySQL.

You see, datetime values are stored as UTC value internally by MySQL. So, when you insert '2011-03-30 12:34:56' in your table with the SYSTEM variable set to 'Europe/Berlin' / '+01:00', MySQL calculates the integer representation for '2011-03-30 11:34:56', saves the value in your DB. When you query for your datetime values, MySQL adds that hour again (assuming your timezone settings haven't changed) and presents you the value '2011-03-30 12:34:56'