MYSQL to MYSQLi
After a PHP upgrade MYSQL will no longer work without displaying errors so many webmasters are being forced to switch to MYSQLi. This can be a scary and daunting task but once you get into it the job moves along at quite a pace.
The basis is quite simply a small change in code:
With MYSQL you may have something like this:
With MYSQLi you would end up with this;
The only difference is the inclusion of the 'i' wherever you have mysql. (This can easily be done with Find and Replace)
Add the $database to $connection you then no longer need the line beginning $db = mysql_select_db
Split the line
$result = mysql_query("SELECT * FROM table") or die(mysql_error());
$query = "SELECT * FROM table";
$result = mysqli_query($connection,$query);
Of course PHP and mysql is a complex and wide ranging subject but I hope that this shows you that convertion is not that difficult to do.