Importing data twice will duplicate records?


I made a copy of my cs cart on a third domain where I am developing an updated version of my store (with new features and new skin).

Once the store will be ready to go online I will redirect the DNS to the subdomain.

In the meantime, new users and new orders have been made on the live web site so I would like to import them before to publish the new version.

The question is: what will happen to the already existing users? They will be skipped, overwritten, duplicated or what??

Thanks in advance!

I suspect the will be given fresh ids ad so be added.

I'm going to do similar soon, I'll export the database tables and add the customers and old sales there. I'll not bother with the passwords because people can request a password change easy enough.

so same user two id?


thank you!