Custom query in Views?

Question

At some point I found the need to modify an SQL query generated by Views, in the end I overrode views_pre_execute and changed the query for that specific view.

This feels like an ugly hack to me and I wonder if there is a more elegant and maintainable way to do that. Ideal would be a way that would allow me to directly modify the query from the Views UI.

Answer 1

You can also use hook_views_query_alter() to alter the query before it's run. I think this is similar to hook_views_pre_execute, but makes it easier to modify the query. You basically get access to each part of the query through a keyed array. I haven't found much official documentation, but there's a pretty good example of it at https://www.appnovation.com/blog/using-hook-views-query-alter. This is also the approach I had to use to fix a date bug in the Calendar module.

Answer 2

In general this depends on your use case.

If you want to have a field/filter/argument which should behave in a certain way, it is recommended to write a handler for it. See advanced help of views for more information.

If you want to change some parts of the query you can also use hook_views_query_alter(). The bad thing about hook_views_query_alter() is that you can't really reuse the code there.

This is the example code shown from the documentation. It gives an example of what the hook can do.

function mymodule_views_query_alter(&$view, &$query) {
  // (Example assuming a view with an exposed filter on node title.)
  // If the input for the title filter is a positive integer, filter against
  // node ID instead of node title.
  if ($view->name == 'my_view' && is_numeric($view->exposed_raw_input['title']) && $view->exposed_raw_input['title'] > 0) {
    // Traverse through the 'where' part of the query.
    foreach ($query->where as &$condition_group) {
      foreach ($condition_group['conditions'] as &$condition) {
        // If this is the part of the query filtering on title, chang the
        // condition to filter on node ID.
        if ($condition['field'] == 'node.title') {
          $condition = array(
            'field' => 'node.nid', 
            'value' => $view->exposed_raw_input['title'], 
            'operator' => '=',
          );
        }
      }
    }
  }
}

Answer 3

I have used the hook_views_query_alter() to alter a views mysql query. The following example is tested under Drupal 7 with 7.x-3.0, it adds a custom ORDER BY clause to the query:

 function MYTHEME_views_query_alter(&$view, &$query) {
   // check so it's the correct view
   if($view->name == 'product_view') {
     // set a custom 'ORDER BY' clause in the query
     $query->orderby[0] = array(
       'field' => 'SUBSTR(taxonomy_term_data_name,3,4)',
       'direction' => 'ASC'
     );
     $query->orderby[1] = array(
       'field' => 'SUBSTR(taxonomy_term_data_name,1,2)',
       'direction' => 'ASC'
     );
   }
 }

Answer 4

I don't know if you can directly change the sql, but you could write your own field handler and craft your own query.