|On sites that I did long ago this may be an issue because I used to hard code MySQL commands directly in the code (like most beginners do) but I have been using a home grown database engine object since about 2001 (which is kept FULLY backward compatible at all times).|
The engine detects if the mysqli function set is available and if it is, it uses it.
If they are not present it uses the mysql set of commands.
I even got the object to work well connecting to a MSSql database (as well as it could using a Windows native database anyway) and to look at the code accessing the database object, you wont realize that it is connecting to MSSql.
On top of that it was a Windows Server with a php plugin. They wanted me to do it in ASP but I refused point blank!
After 8 months of their in house ASP "Experts" trying, they loaded the php plugin and I had it up in about a week.
Oh the joys of using standard code objects !
And do not forget that "PHP Rocks!"