How to change mysql to mysqli?

Question

Based on this code below I use for regular mysql, how could I convert it to use mysqli?

Is it as simple as changing mysql_query($sql); to

Answer 1

Although this topic is a decade old, I still often require to 'backpatch' existing applications which relied upon the mysql extension — the original programmers were too lazy to refactor all their code, and just tell customers to make sure that they run the latest PHP 5.6 version available.

PHP 5.6 is now officially deprecated; in other words, developers had a decade to get rid of their dependencies upon mysql and move to PDO (or, well, mysqli...). But... changing so much legacy code is expensive, and not every manager is willing to pay for the uncountable hours to 'fix' projects with dozens of thousands of lines.

I've searched for many solutions, and, in my case, I often used the solution presented by @esty-shlomovitz — but in the meantime, I've found something even better:

https://www.phpclasses.org/package/9199-PHP-Replace-mysql-functions-using-the-mysqli-extension.html

(you need to register to download it, but that just takes a minute)

These are just two files which act as drop-in replacements for the whole mysql extension and very cleverly emulate pretty much everything (using mysqli) without the need to worry much about it. Of course, it's not a perfect solution, but very likely it will work in 99% of all cases out there.

Also, a good tutorial for dealing with the chores of migration (listing many of the common pitfalls when migrating) can also be found here: https://www.phpclasses.org/blog/package/9199/post/3-Smoothly-Migrate-your-PHP-Code-using-the-Old-MySQL-extension-to-MySQLi.html

(if you're reading this in 2030 and the PHPclasses website is down, well, you can always try archive.org :-)

Update: @crashwap noted on the comments below that you can also get the same code directly from GitHub. Thanks for the tip, @crashwap :-)