Magento – How to remove Magento2 sample data without uninstall

It is possible to change the database that Magento uses after it has been installed. So the steps for your scenario would be:

1. install sample data into a separate database
2. copy the product images into your Magento installation
3. edit app/etc/local.xml and change the database to the one with the sample data present
4. delete var/cache
5. opening the site in the browser should now trigger the installation routine and you will end up with a store including the demo data

Uninstalling the sample data is not easily doable. You can delete all products which gets you some of the way there. However overall I would suggest keeping the store with the sample data separate. If you don't mind the product images from the demo store clogging up your system you can reverse step 3. and then deleting the cache to get back to your original database.

Run this in the console bin/magento sampledata:reset

Please make sure take a backup of your db.

Enter the following command for remove:

bin/magento sampledata:remove

Wait while sample data is removed.

For more See here.