Requirements
I have experienced exactly the same problem as flo_stefi at yahoo dot com below. It appears that instead of loading libmysql.dll that came with the PHP package, the PHP engine was loading libmySQL.dll located in MySQL's bin directory, which was causing Apache to crash.
I fixed the problem by renaming MySQL's libmySQL.dll into libmySQL_renamed.dll. Now PHP loads the library that came with its package and everything works fine.
Installation
For compiling, simply use the --with-mysql[=DIR] configuration option where the optional [DIR] points to the MySQL installation directory.
Although this MySQL extension is compatible with MySQL 4.1.0 and greater, it doesn't support the extra functionality that these versions provide. For that, use the MySQLi extension.
If you would like to install the mysql extension along with the mysqli extension you have to use the same client library to avoid any conflicts.
Installation on Linux Systems
PHP 4
The option --with-mysql is enabled by default. This default behavior may be disabled with the --without-mysql configure option. If MySQL is enabled without specifying the path to the MySQL install DIR, PHP will use the bundled MySQL client libraries.
Users who run other applications that use MySQL (for example, auth-mysql) should not use the bundled library, but rather specify the path to MySQL's install directory, like so: --with-mysql=/path/to/mysql. This will force PHP to use the client libraries installed by MySQL, thus avoiding any conflicts.
Installation on Windows Systems
PHP 4
The PHP MySQL extension is compiled into PHP.
PHP 5+
MySQL is no longer enabled by default, so the php_mysql.dll DLL must be enabled inside of php.ini. Also, PHP needs access to the MySQL client library. A file named libmysql.dll is included in the Windows PHP distribution and in order for PHP to talk to MySQL this file needs to be available to the Windows systems PATH. See the FAQ titled "How do I add my PHP directory to the PATH on Windows" for information on how to do this. Although copying libmysql.dll to the Windows system directory also works (because the system directory is by default in the system's PATH), it's not recommended.
As with enabling any PHP extension (such as php_mysql.dll), the PHP directive extension_dir should be set to the directory where the PHP extensions are located. See also the Manual Windows Installation Instructions. An example extension_dir value for PHP 5 is c:\php\ext
Note: If when starting the web server an error similar to the following occurs: "Unable to load dynamic library './php_mysql.dll'", this is because php_mysql.dll and/or libmysql.dll cannot be found by the system.
MySQL Installation Notes
Warning
Crashes and startup problems of PHP may be encountered when loading this extension in conjunction with the recode extension. See the recode extension for more information.
Note: If you need charsets other than latin (default), you have to install external (not bundled) libmysql with compiled charset support.
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User Contributed NotesInstallation
amatsak at gmail dot com
22-Jun-2009 04:46
22-Jun-2009 04:46
flo_stefi at yahoo dot com
01-Apr-2009 06:10
01-Apr-2009 06:10
I had a problem to make mysql work with php on Windows. Using mysql-5.1.32-win32 and php-5.2.9-1-win32-installer I've installed mysql and php. All seemed to be ok (phpinfo displayed the right information) but when running a basic script mysql_connect(..) the apache ends with a stupid error like "[Wed Apr 01 14:44:05 2009] [notice] Parent: child process exited with status 3221225477 -- Restarting.".
I manage to fix it by using instead of libMySQL.dll from mysql package another version (libmysql.dll) I had from a previous installation.
lobbanhousehold at gmail dot com
11-Feb-2009 09:05
11-Feb-2009 09:05
I figured my problem why php and mysql weren't working together even though they worked independent of each other. PHP was configured with IIS 5.1 (XP) using the php5isapi.dll file.
I also set system variables in PATH adding the locations of both php and mysql folders. I also moved the mysql DLL files from ext folder to the root folder of php.
I discovered that php would not work with mysql if php folder was not located on the C:\ (i.e. C:\php). I also renamed the libmysql.dll that came with mysql so that the system would not see it, and moved the one that came with php to C:\WINDOWS\system32.
After I did this last paragraph i was able to see MySQL and MySQLi sections listed in phpinfo() which indicates MySQL is finally enabled
admin at kobashicomputing dot com
02-Nov-2008 01:02
02-Nov-2008 01:02
Unfortunately this one bit me for a good half day.
Placing libmysql.dll in the php/ext directory did not work. I tested this under 5.6.2. You need to have it somewhere in the PATH or in SYSTEM or SYSTEM32. But to me this is very silly to force the user to have to setup environment variables or move DLLs around. It shouldn't have to go that far and be the responsibility of the setup program and/or developer.
I really think this issue could be solved doing this:
1) Installer/distribution bundle all three files together under one directory (ext) - php_mysql.dll/php_mysqli.dll/libmysql.dll
2) Developer goes into php_mysql.dll/php_mysqli.dll and in DllMain() on DLL_PROCESS_ATTACH:
LoadLibrary ("./libmysql.dll");
Then you don't have to deal with this problem and neither do your users.
Kerry Kobashi
rogerc at clubsites dot net
20-Jul-2008 09:05
20-Jul-2008 09:05
This error also occurs if the windows path entry for an older version of MYSQL appears before the path entry for a late version of php. In which case the version of libmysl.dll in the MySQL bin directory will be found before the one bundled with php. Reversing the system path entries so php is first fixes this problem. e.g.
PATH= ... c:\php;C:\Program Files\MySQL\MySQL Server 4.1\bin
Mahesh
13-Jun-2008 04:37
13-Jun-2008 04:37
In windows systems, the error "unable to load dynamic library php_mysql.dll" also happens if there's an old version of the file libmysql.dll in the "windows\system32" folder.
jonnus
12-May-2008 07:42
12-May-2008 07:42
In windows systems, the same error "unable to load dynamic library php_mysql.dll" will happen, if there's an old version of the file in the "windows\system32" folder.
Either remove it or update it.