Convert a double (or string) into a Unix epoch timestamp in MySQL?

Question

I've seen the instructions for converting back and forth between a UNIX epoch and a datetime in MySQL -- it's not too hard (from_unixtime to convert from epoch to datetime, unix_timestamp to get the current epoch time).

Unfortunately, I have saved all of my timestamps from my server as doubles -- and upon attempting to cast doubles to timestamps, I fail.

select
    from_unixtime(cast('1416355920908' as datetime)),
    from_unixtime(cast(1416355920908 as datetime)),
    from_unixtime(unix_timestamp());

This returns NULL, NULL, '2014-11-19 10:18:34' on MySQL.

Is there a way to convert a number or string to an epoch or datetime?

Answer 1

It turns out I made the epochs so big they exploded MySQL... it's a mistake I initiated in NodeJS, when I used its functions to gather up epochs instead of relying on MySQL. The simple fix is:

select from_unixtime(1416355920908 / 1000);