Ok make a back up of both.
Then
part 1go to your SMF DB and select export.
Select all
Select save Structure. uncheck any under that.
Select save Data uncheck any under that.
Now export as a gzip. SQL cannot import ZIP or raw Text in one hit, only Gzip.
So that brings us to import into Joomla.
Open Joomla DB select Import.
You should have no problems..
Part 2 Managing users.In mySQL: select the user for SMF and save it to the Joomla Account by using [ADD USER]. now Joomla DB should have both as access right enabled.
Part 3 Get you SMF config file (settings.php) and change the DB name to Joomla.
e.g
$db_server = 'localhost';
$db_name = 'smf44980_smf_1';
$db_user = 'smf44980_smf_1';
$db_passwd = 'XNIDY683DD';
$db_prefix = 'smf_';
$db_persist = 0;
$db_error_send = 1;
to
$db_server = 'localhost';
$db_name = 'joom4980_joom1';<<<<<<<<<<<<
$db_user = 'smf44980_smf_1';
$db_passwd = 'XNIDY683DD';
$db_prefix = 'smf_';
$db_persist = 0;
$db_error_send = 1;
You should now have smf and Joomla in one table...
