Solution to 'Missing mysqli extension. Please check PHP configuration' under Linux

tar -zxvf php-5.2.17.tar.gz
cd php-5.2.17/ext/mysqli/
/usr/bin/phpize #The configure configuration file will be generated in the current directory
./configure –with-php-config=/usr/bin/php-config –with-mysqli=/usr/bin/mysql_config
make
make install

If the above is correct, you can install it in /usr/ Find mysqli.so under lib64/php/modules/, and then add: extension=mysqli.so Then, restart the httpd service.