Views Query Alter for Drupal example.

Views Query Alter

<?php
    /*
     * Implements hook_views_query_alter();
     *
     */
function custom_partnerportal_views_query_alter(&$view, &$query) {
    if ($view->name == 'taxonomy_term') {
        global $user;
        $usuario = user_load($user->uid);
        $categories = $usuario->field_category['und'];
        $cats = array();
        foreach($categories as $item) {
            $cats[] = $item['tid'];
        }
        $actualarguments = $view->args;
        $result_array = array_diff($actualarguments,$cats);
        $countdif = count($result_array);
        if($countdif == 0) {
        } else {
            $view->executed = TRUE;
            drupal_set_message(t('You dont have access to this content.'),'error');
        }
    }
}