We’re WordPress experts here, but we recently came accross the following error when migrating a client site to our hosting for them:-
joomla Database Error: Unable to connect to the database:The MySQL adapter "mysqli" is not available
Actually the fix turned out to be pretty simple. Open up the Joomla ‘configuration.php file and then:-
Change the following line:-
var $dbtype = 'mysqli';
var $dbtype = 'mysql';
If you are still have database issues after this fix then check that you are using the correct database name, database user name and password. Ensure that the user on the database is assigned to the database with all required privileges.