• You can run this code within the specific database:

    Select

    P.name as username,

    RP.name as role_name

    from

    sys.database_role_members R Join

    sys.database_principals RP On

    R.role_principal_id = RP.principal_id Join

    sys.database_principals P On

    R.member_principal_id = P.principal_id

    Where

    RP.name = 'db_owner'