function getColumnChart()
{
    $globalStatEngine = new GlobalStatEngine();
    $sid = $_POST["sid"];
    $tableName = $_POST["table_name"];
    $columnName = $_POST["columnName"];
    $data = $globalStatEngine->getColumnChart($sid, $tableName, $columnName);
    echo json_encode($data);
}
<?php

include_once realpath(dirname(__FILE__)) . '/GlobalStatEngine.php';
include_once realpath(dirname(__FILE__)) . '/../config.php';
//include('config.php');
include_once realpath(dirname(__FILE__)) . '/../Smarty.class.php';
$main_smarty = new Smarty();
include_once realpath(dirname(__FILE__)) . '/../libs/html1.php';
include_once realpath(dirname(__FILE__)) . '/../libs/link.php';
include_once realpath(dirname(__FILE__)) . '/../libs/smartyvariables.php';
// breadcrumbs and page title
$navwhere['text1'] = $main_smarty->get_config_vars('PLIGG_Visual_Breadcrumb_SiteStatistics');
$navwhere['link1'] = getmyurl('global_statistics', '');
$main_smarty->assign('navbar_where', $navwhere);
$main_smarty->assign('posttitle', $main_smarty->get_config_vars('PLIGG_Visual_Breadcrumb_SiteStatistics'));
$main_smarty = do_sidebar($main_smarty);
// pagename
define('pagename', 'globalStatistics');
$main_smarty->assign('pagename', pagename);
$globalStatEngine = new GlobalStatEngine();
$outputs = $globalStatEngine->GetGlobalStatisticsSummary();
$main_smarty->assign('numberOfStories', $outputs->numberOfStories);
$main_smarty->assign('numberOfDvariables', $outputs->numberOfDvariables);
$main_smarty->assign('numberOfRelationships', $outputs->numberOfRelationships);
$main_smarty->assign('numberOfRecords', $outputs->numberOfRecords);
$main_smarty->assign('numberOfUsers', $outputs->numberOfUsers);
$main_smarty->assign('tpl_center', $the_template . '/global_statistics_center');
$main_smarty->display($the_template . '/pligg.tpl');