In MySQL caculating offset for a time zone

Question

Is there a way in MySQL to calculate the offset for any timezone? For example, to get the local time in the timezone Asia/calcutta. What I want to do is calcula

Answer 1

I mixed up @ColinM and @Kenneth Spencer's answers because I wanted the offset of an arbitrary timezone in hours:

TIMESTAMPDIFF(HOUR, UTC_TIMESTAMP(), CONVERT_TZ(UTC_TIMESTAMP(), "UTC", "America/Denver"))

-

SELECT ROUND(TIMESTAMPDIFF(MINUTE, UTC_TIMESTAMP(), CONVERT_TZ(UTC_TIMESTAMP(), "Etc/UTC", "Asia/Kolkata"))/60,1)

As Kenneth pointed out you'll need to load the timezone info: http://dev.mysql.com/doc/refman/5.0/en/mysql-tzinfo-to-sql.html

But then you can do fun things like find the offset for multiple timezones at once:

SELECT Name,
TIMESTAMPDIFF(HOUR, UTC_TIMESTAMP(), CONVERT_TZ(UTC_TIMESTAMP(), "Etc/UTC", Name)) as Offset
FROM mysql.time_zone_name 
WHERE (Name IN ('America/Vancouver', 'Etc/UTC', 'America/Denver'))

Giving:

+-------------------+--------+
| Name              | Offset |
+-------------------+--------+
| America/Denver    |     -6 |
| America/Vancouver |     -7 |
| Etc/UTC           |      0 |
+-------------------+--------+

Answer 2

SELECT TIMESTAMPDIFF(HOUR, UTC_TIMESTAMP(), NOW());

If the server's timezone is PST this will return -8.

SELECT TIMESTAMPDIFF(SECOND, NOW(), UTC_TIMESTAMP());

Add the result of the above to any unix timestamp if you want to compare it to MySQL DateTimes.