OKTA to use my SQL database to register/sign in/authorize/authenticate users

I am looking to switch to OKTA in a near term. however I already have SQL database with usernames/passwords and encryptions. Is it possible to have OKTA use my SQL database for user auth/registration/sign in process till we migrate our users to OKTA?

Thank you!

Are you saying the users will be created in Okta but they will authenticate against your SQL database?

they are (users) will be created in our SQL Database as well (next to ones that already exist), using username instead of email. (we are not using emails for logins/registrations)
Till we are ready to migrate all user database to OKTA and move to OKTA’s user store completely.