Customize the Views Query in durpal

One work around is overriding the view query by implementing thehook_views_pre_execute(&$view) in a custom module. Before you construct the new SQL, you should set all your desire settings in the view editing page first. Then you can create a new SQLbase on that view query.

    /**
    * Override the query SQL in a view
    *
    * 1. Check the view name by drupal_set_message($view->name);
    * 2. Get the original SQL by drupal_set_message($view->build_info['query']);
    * 3. Modify the original SQL as of your preference
    * 4. Set the new SQL to $view->build_info['query']
    */
    function custom_views_pre_execute(&$view) {
    /* 1. Check the view name */
    //drupal_set_message($view->name);

    /* 2. Get the original SQL */
    //drupal_set_message($view->build_info['query']);

    /* 3. Modify the original SQL as of your preference */
    // I just change the LEFT JOIN to RIGHT JOIN =P

    /* 4. Set the new SQL to $view->build_info['query'] */
    if ($view->name == "view_name") {
    $view->build_info['query'] = "SELECT term_data.tid AS tid, term_image.tid AS term_image_tid, term_data.name AS term_data_name, term_data.vid AS term_data_vid FROM {term_data} term_data RIGHT JOIN {term_image} term_image ON term_data.tid = term_image.tid WHERE (term_data.vid in ('%s')) AND (term_data.language in ('%s')) ORDER BY term_data_name ASC ";
    }
    }

    Since you have override the query SQL, any new changes to the view through the view editing page will no longer valid. This is why we should set all desire settings in the view editing page before overriding it.
    Reference: implementing custom sql query for views / filters