MySQL from_unixtime after 2038-01-19?

问题

We have dates stored as a unix timestamp. To allow a user to search for a certain date - based on his timezone-setting, we used to convert that timestamp inside the query, to make sure a search for "2012-05-03" will not find results of the prior / next day depending on which timezone the user has setup.

i.e. if a date is stored as 2012-05-03 23:00 (UTC) A user with the proper timezone offset searching for 2012-05-04 should find this entry.

This is done like this at the moment:

CONVERT_TZ(FROM_UNIXTIME(`javaTimeStampColumn`/1000),'+00:00','+00:00')

where ofc. the offsets are set depending on the users timezone.

The problem we are facing at the moment: Java successfully stores dates after the year 2038 as a unix-timestamp. The MySQL method from_unixtime however does not support any conversion of values greater than 2147483647 due to it's integer type limitation:

SELECT FROM_UNIXTIME(2147483647); //2038-01-19 04:14:07

SELECT FROM_UNIXTIME(2147483648); //null

The MySQL server itself is 64bit, but ofc. FROM_UNIXTIME would need to accept a long as argument.

I could not find a proper replacement by now, any hints?

We could ofc. load the timestamp as a Long and handle it in the application - But for lazylaoding we need to be able to convert it correctly during the query as well.

回答1:

A workaround might be to use DATE_ADD, but I'm not sure how it behaves performance-wise:

SELECT DATE_ADD(FROM_UNIXTIME(0), INTERVAL 2147483647 SECOND); //2038-01-19 04:14:07
SELECT DATE_ADD(FROM_UNIXTIME(0), INTERVAL 2147483648 SECOND); //2038-01-19 04:14:08
...
SELECT DATE_ADD(FROM_UNIXTIME(0), INTERVAL 4147483647 SECOND); //2101-06-06 07:47:27

So for now, I'm using

...
CASE 
  WHEN `javaTimeStampColumn` > 2147483647 THEN
    CONVERT_TZ(DATE_ADD(FROM_UNIXTIME(0), INTERVAL `javaTimeStampColumn`/1000 SECOND),'+00:00','+00:00')
  ELSE  
    CONVERT_TZ(FROM_UNIXTIME(`javaTimeStampColumn`/1000), '+00:00','+00:00')
END as ts
FROM table
...

which should minimize the impact on performance if there is any.

来源：https://stackoverflow.com/questions/31811527/mysql-from-unixtime-after-2038-01-19

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mysql

timestamp