Question

i have a created field in datetime and a modified field in timestamp.
this is my code

date_default_timezone_set('America/Los_Angeles');
if ($this->isNewRecord)
$this->created = date("Y-m-d h:i:s");
$this->modified = date("Y-m-d h:i:s");

when i create a new record i see datetime and timestamp with same time in Los Angeles time but i expect timestamp field to be in UTC.
i mean if datetime field is something like ‘.. 08:00:00′ timestamp should be ’16:00:00’ because US time is (UTC -08:00) and DOC says

TIMESTAMP values are converted from the current time zone to UTC for
storage

Answer 1

TIMESTAMP fieds are in fact converted to UTC for storage. That means, it’s stored this way, but when selected it will be converted to connection’s timezone. You can do an experiment: change your timezone (see below) to something else, and do the select for that timestamp.

Here’s MySQL docs about handling timezones

---

added: some console output for illustration

mysql> use test
Database changed
mysql> -- Let s see what is the current timezone setting on this server
mysql> SELECT @@global.time_zone, @@session.time_zone;
+--------------------+---------------------+
| @@global.time_zone | @@session.time_zone |
+--------------------+---------------------+
| SYSTEM             | SYSTEM              |
+--------------------+---------------------+
1 row in set (0.00 sec)

mysql> -- I don t know what SYSTEM is set to, so just to be safe I ll set it to my timezone
mysql> set time_zone = '+01:00';
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT @@global.time_zone, @@session.time_zone;
+--------------------+---------------------+
| @@global.time_zone | @@session.time_zone |
+--------------------+---------------------+
| SYSTEM             | +01:00              |
+--------------------+---------------------+
1 row in set (0.00 sec)

mysql> -- Let s create a table for or test    
mysql> create table testTimestamp (ts timestamp);
Query OK, 0 rows affected (0.28 sec)

mysql> -- Now to insert current time into the test table
mysql> insert into testTimestamp values (now());
Query OK, 1 row affected (0.01 sec)

mysql> -- Let s see how it looks like
mysql> select * from testTimestamp;
+---------------------+
| ts                  |
+---------------------+
| 2012-02-13 00:12:00 |
+---------------------+
1 row in set (0.03 sec)

mysql> -- Now let s change session timezone to Los Angeles time
mysql> set time_zone = '-08:00';
Query OK, 0 rows affected (0.00 sec)

mysql> -- And let s look at our timestamp once again
mysql> select * from testTimestamp;
+---------------------+
| ts                  |
+---------------------+
| 2012-02-12 15:12:00 |
+---------------------+
1 row in set (0.00 sec)