I'm running Vista 64 box, and attempting to setup Joomla using IIS7 (I like Joomla, I want to have some asp.net components on my web site, so that's why I want to use IIS7 and not Apache). It's my first time installing both PHP and MySQL, so it's very possible that I'm doing something obviously wrong... though I think I tried enough diagnostic steps (described below) that there's nothing obviously wrong to me...
I installed PHP (32 bit, 5.2.8), and that seems to work OK: I got a test.php that displays phpinfo in an IIS7-served web page.
I also installed MySQL (32 bit, 5.1.31, downloaded from http://dev.mysql.com/downloads/mysql/5.1.html#win32 ). That seems to work fine too (I can connect to it using MySQL Administrator).
I've setup php.ini and what not to turn on the MySQL extension. If I do PHP -m from the command line I see MySQL in the list. However, with phpinfo (either from the command line (PHP -info) or served via IIS (in a test.php file)), there is no MySQL section. Because MySQL is not even showing up in the command-line call of PHP, I don't think this has anything to do with IIS -- just an install of MySQL & PHP on vista.
I didn't install MySQL 64bit because I have an 32bit install of PHP, and since MySQL 32 bit seems to work fine I assume that's not the issue. It seems there is no official 64bit version of PHP so that's why I installed that (and again, that seems to work fine).
I currently have UAC disabled, so that's not the issue.
If I put the semi-colon back in front of extension=php_mysql.dll in my php.ini then when running PHP -m, the MySQL module doesn't show up. If I take it out again then it shows up. So I'm at least certain I'm modifying the right php.ini.
I've copied libeay32.dll, libmysql.dll, and php_mysql.dll to c:\windows\system32. I've taken them out and that doesn't seem to make a difference to the output of PHP -m (i.e., MySQL still shows up there if the module is uncommented from php.ini).
I also tried copying the DLLs ibeay32.dll, libmysql.dll, and php_mysql.dll to c:\windows\sysWOW64; that made no difference.
It seems like the smallest positive step would be for MySQL to show up when running PHP -info from the command line. Is there any further thing I should try to figure out why MySQL is showing up in PHP -m and not with PHP -info? Or am I off track as using this to gauge whether PHP can talk to MySQL?
I've solved most of it.
The answer was to copy libmysql.dll to sysWOW64. The other DLLs are not needed, and nothing needs to be copied to system32. I guess this is a result of using php32 on a 64 bit system.
I thought that didn't work at first because running PHP -info from the command line still doesn't show MySQL. However, running phpinfo from a PHP file served by IIS does show MySQL.
I still don't know why MySQL doesn't show up when running PHP -info from the command line, but I guess I can live with this for now.