how to get a file path of wp-config.php of wordpress site? -

i developing plugin in need include config , query wordpress database on click ..my question how url of wp-config.php dynamically ..i have used

include_once $_server['document_root'] . '/wp-config.php';

but getting error

include_once(): failed opening /wp-config.php' inclusion (include_path='.:/usr/share/php:/usr/share/pear')

and have tried many options

require_once('../../../wp-config.php'); require_once ("../wp-config.php");

i dunno wat exact path ..

any appreciated ..

in short, shouldn't trying include wp-config.php plugin. there few if reasons ever take approach. purists go far should never done.

a wordpress plugin has proper context access global $wpdb variable querying. take @ example:

global $wpdb;  $results = $wpdb->get_results( $wpdb->prepare("select * {$wpdb->prefix}your_table column = %s", $your_value) );

Brande