Although Perl offers the widest range of date conversion facilities - we are only scratching the surface so far, I feel it is only responsible to add that MySQL is also well-stacked with date-conversion functions. So whether to use Perl functions or MySQL functions for this depends more on the OTHER functionality you are dealing with (e.g. are stored procedures involved -- particularly if they have error-handling that if activated might obviate the need to convert in some cases -- and what other functionality is already implemented in Perl versus MySQL whose development should be encapsulated in just one place or the other?). So apart from the excellent suggestions by other posters, based on the limited information so far, it remains possible that you might want to include such MySQL functions as STR_TO_DATE in your list of contending solutions before making your choice of where/how to do this.

Update: reworded to make post more concise.