You need to be at MySQL version 5.6.4 or later to declare columns with fractional-second time datatypes. Not sure you have the right version? Try SELECT NOW(3). If you get an error, you don’t have the right version.
For example, DATETIME(3) will give you millisecond resolution in your timestamps, and TIMESTAMP(6) will give you microsecond resolution on a *nix-style timestamp.
Read this: https://dev.mysql.com/doc/refman/8.0/en/fractional-seconds.html
NOW(3) will give you the present time from your MySQL server’s operating system with millisecond precision.
If you have a number of milliseconds since the Unix epoch, try this to get a DATETIME(3) value
FROM_UNIXTIME(ms * 0.001)
Javascript timestamps, for example, are represented in milliseconds since the Unix epoch.
(Notice that MySQL internal fractional arithmetic, like * 0.001, is always handled as IEEE754 double precision floating point, so it’s unlikely you’ll lose precision before the Sun becomes a white dwarf star.)
If you’re using an older version of MySQL and you need subsecond time precision, your best path is to upgrade. Anything else will force you into doing messy workarounds.
If, for some reason you can’t upgrade, you could consider using BIGINT or DOUBLE columns to store Javascript timestamps as if they were numbers. FROM_UNIXTIME(col * 0.001) will still work OK. If you need the current time to store in such a column, you could use UNIX_TIMESTAMP() * 1000