We have an `Article` content type which has an Entity Reference field called `field_document` that is linked to the `Media` bundle type of `Document`. In `mymodule` we need to write a hook that will take the current `field_document.id` (which maps to `Document.mid`) and return all the `Article` pages where `field_document.target_id = mid`. 

**Goal**

 - Take the current node id and retrieve the `Document` entity that is linked to by accessing `field_document`
 - Using the `field_document` value, return other `Articles` that have the same value for `field_document`
 - Perform the query in a `hook_preprocess_node()` hook. 

**Question**

 1. How can we retrieve all the nodes based on the $mid?

**When we tried**

  We were able to return all `Articles`. However when we add `->condition('field_document.target_id, $mid)`, we get zero results even though we know there are `Articles` where the `field_document.target_id = $mid`. 

    function mymodule_preprocess_node($variables) {
      $node = $variables['node'];
      $linked_document_id = $node->get('field_document')->first()->getValue()['target_id'];
    
      $node_storage = \Drupal::entityTypeManager()->getStorage('node');
      $query = $node_storage->getQuery()
        ->condition('type', 'article')
        ->condition('status', 1);
    
      $and = $query->andConditionGroup();
      $and->condition('field_document', $linked_document_id, '=');
      $query->condition($and);
      $results = $query->execute();
    
      // returns zero
      ksm($results);
    }

We also tried using `$and->condition('field_document.target_id', $linked_document_id, '=');`, but that did not return any results either. 

Additional steps we tried, but with similar issue. 

     function mymodule_preprocess_node($variables) {
      $node = $variables['node'];
      $linked_document_id = $node->get('field_document')->first()->getValue()['target_id'];
    
      $node_storage = \Drupal::entityTypeManager()->getStorage('node');
      $query = $node_storage->getQuery()
        ->condition('type', 'article')
        ->condition('status', 1);
        ->condition('field_document', $linked_document_id, '=');
      $results = $query->execute();
    
      // returns zero
      ksm($results);
    }