Can MySQL convert a stored UTC time to local timezone?

Is your database clock accurate?

For CONVERT_TZ() to work, your timezone data needs to be present. Without it, MySQL is like one broken clock telling the wrong time. Update this data using mysql_tzinfo_to_sql or the Easter bunny might bring you "Null" instead of chocolates.

Don't take CONVERT_TZ() for granted. Always verify its compatibility with your MySQL version before inviting it to the party. And remember, while it's dancing on your dataset, you might face performance impacts.

Special cases and how to handle them

Dealing with DST

Daylight Saving Time can sneak up on you like a ninja, knocking an hour here and there. Always use timezone names (like 'America/New_York') over UTC offsets to tackle DST. It's like having your own time bodyguard!

No names, no problem. Use offsets

When names are not an option, UTC offsets come to the rescue. But remember, '+00:00' stands for UTC. For others, put on your math hat and adjust the offset!

Serve your user base

'CONVERT_TZ()' can cater to your international users' needs. Serve data on a silver platter in their own timezone:

SET @user_timezone = 'Asia/Tokyo';
SELECT CONVERT_TZ(utc_column, '+00:00', @user_timezone) AS local_time FROM table;
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Limitations and how to deal with them

How to filter with time

When you're filtering dates, compare timestamps in UTC before getting a makeover:

WHERE utc_column < UTC_TIMESTAMP() /* UFO sightings are best reviewed on UTC time*/
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After the comparison, let CONVERT_TZ() help you see results in local color:

SELECT CONVERT_TZ(utc_column, '+00:00', 'US/Pacific') AS local_time /* See sightings in your time*/
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Time-only conversions, because why not?

To convert just the time, have TIME function join hands with CONVERT_TZ():

SELECT TIME(CONVERT_TZ(utc_time_column, '+00:00', 'US/Eastern')) AS local_time_only /* Just because we can*/
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Limitations to consider

• CONVERT_TZ() belting out a solo in complex queries might affect performance.
• Literal strings representing time are like two left feet in a salsa class. Handle with care.

Keep your timezone data fresh

MySQL’s timezone info doesn't auto-update. To stay on the ball, use the mysql_tzinfo_to_sql script:

mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -u root -p mysql /* Time for a spring clean!*/
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The server directory /usr/share/zoneinfo gives you all the accuracy you need.