How exactly date/time works in MySQL with timezones?

Question

My understanding was:

• everything is UTC internally
• dates are displayed in @@session.time_zone timezone for current session
• if I do INSERT with +02:00 TZ set and insert 2015-05-15 10:54 it is parsed and stored as 2015-05-15 08:54 UTC.
• when I change to UTC TZ it should now display 2015-05-15 08:54
• what happens instead is that it still displays 2015-05-15 10:54

What am I doing wrong? Or is this expected? I read quite some articles about datetime in MySQL but I am still not sure.

Answer 1

That only applies to TIMESTAMP fields. DATETIME fields are left as-is.

See http://dev.mysql.com/doc/refman/5.7/en/datetime.html