All of these options are fine, if you have the option to re-export the data.
But if you need to use an existing SQL file, and use a specific table from it, then this perl script in the TimeSheet blog, with enable you to extract the table to a separate SQL file, and then import it.
The original link is dead, so it is a good thing that someone has put it instead of the author, Jared Cheney, on GitHub, in this link.