Excluding empty(Null) fields when using EntityFieldQuery query condition

Question

Is it possible to select all of the entities who's xyz field is empty?

I tried soemthing like this:

->fieldCondition('field_name', 'value', NULL, 'IS NOT NULL');

However, this doesn't seem to work.

Any ideas?

Answer 1

If you look on the fieldCondition documentation page you will see the following warning:

Note that entities with empty field values will be excluded from the EntityFieldQuery results when using this method.

Checking whether a field exists or not has been added to entityFieldQuery in Drupal 8, but unfortunately won't be backported to Drupal 7.

There are various methods to achieve this:

1. Using a tag and hook_query_TAG_alter as mentioned by @Clive, see comment 4 on the Drupal issue for an example ;
2. First query all non NULL entries, then query all entries excluding the previous ones, as described in @seddonym's answer and in comment 5 on the Drupal issue ;
3. You can write your query using SelectQuery rathen than EntityfieldQuery as such:

_

$q = db_select('node', 'n');
$q->fields('n', array('type'))
  ->condition('n.type', 'my_node_type', '=')
  ->addJoin('LEFT', 'field_data_field_my_field', 'f', 'f.entity_id = n.nid');
$q->isNull('f.value');
$r = $q->execute();

Answer 2

You can use != NULL, but you can't use = NULL for some reason.

This is my workaround.

  //Get all the entities that DO have values
  $query = new EntityFieldQuery();
  $query->entityCondition('entity_type', 'MY_TYPE')
    ->fieldCondition('field_MY_FIELD', 'value', 'NULL', '!=');
  $result = $query->execute();

  if (is_array(@$result['registration'])) {
    //Now get all the other entities, that aren't in the list you just retrieved
    $query = new EntityFieldQuery();
    $query->entityCondition('entity_type', 'MY_TYPE')
      ->entityCondition('entity_id', array_keys($result['MY_TYPE']), 'NOT IN');
    $result_two = $query->execute(); 
  }

Answer 3

The short answer is that directly, no you can't (see EntityFieldQuery does not support isNull or isNotNull). If I remember rightly this is a side-effect of the fact that EntityFieldQuery uses only INNER JOINs to join tables.

There is a workaround, though, which involves using hook_query_TAG_alter() and adding a tag to your EntityFieldQuery, there's an example in the last comment on the page I linked to above.

Answer 4

According to the documentation you can use null and isnull; it just has a specific way to write it.

$query = new EntityFieldQuery();
$query->entityCondition('entity_type', 'node')
  ->entityCondition('bundle', 'article')
  ->propertyCondition('status', 1)
  ->fieldCondition('field_news_types', 'value', 'spotlight', '=')
  ->fieldCondition('field_photo', 'fid', 'NULL', '!=')
  ->fieldCondition('field_faculty_tag', 'tid', $value)
  ->fieldCondition('field_news_publishdate', 'value', $year. '%', 'like')
  ->range(0, 10)
  ->addMetaData('account', user_load(1)); // run the query as user 1

$result = $query->execute();

if (isset($result['node'])) {
  $news_items_nids = array_keys($result['node']);
  $news_items = entity_load('node', $news_items_nids);
}

Answer 5

In Drupal 7 please check the following workaround proposed here:

Register the tag to alter the query instance:

<?php
/**
 * Implements hook_query_TAG_alter()
 */
function MYMODULE_query_node_is_not_tagged_alter(QueryAlterableInterface $query) {
  $query->leftJoin('field_data_field_tags', 'o', 'node.nid = o.entity_id AND o.entity_type = :entity_type');
  $query->isNull('o.field_tags_tid');
}
?>

Obs.: This query tag alter only works for the "node" entity type. Don't confuse "field_tags" related to the "Tags" vocabulary, can be any other like "Categories".

Get all the nodes from that doesn't been tagged yet using EntityFieldQuery, look at the addTag() method:

<?php
$query = new EntityFieldQuery();
$query->entityCondition('entity_type', 'node')
  ->entityCondition('bundle', 'news')
  ->addTag('node_is_not_tagged')
  ->propertyCondition('status', 1);
$result = $query->execute();
?>

Other example:

  $result = $query
    ->entityCondition('entity_type', 'node')
    ->propertyCondition('type', 'my_content_type')
    ->fieldCondition('field_mine_one', 'value', '', '<>')
    ->fieldCondition('field_mine_two', 'value', '', '<>')
    ->addTag('my_custom_tag')
    ->deleted(FALSE)
    ->propertyOrderBy('changed', 'DESC')
    ->range(0, $my_range_value)
    ->execute();

Then I implemented hook_query_TAG_alter leveraging the fact that my_custom_tag is only set by me:

/**
 * Implements hook_query_TAG_alter()
 */
function MYMODULE_query_TAG_alter(QueryAlterableInterface $query) {
  $query->leftJoin('field_data_field_other', 'o', 'node.nid = o.entity_id');
  $query->isNull('o.field_other_value');
}

Another example:

<?php
  //Get all the entities that DO have values
  $query = new EntityFieldQuery();
  $query->entityCondition('entity_type', 'MY_TYPE')
    ->fieldCondition('field_MY_FIELD', 'value', 'NULL', '!=');
  $result = $query->execute();

  if (is_array(@$result['registration'])) {
    //Now get all the other entities, that aren't in the list you just retrieved 
    $query = new EntityFieldQuery();
    $query->entityCondition('entity_type', 'MY_TYPE')
      ->entityCondition('entity_id', array_keys($result['MY_TYPE']), 'NOT IN');
    $result_two = $query->execute();  
  }
?>

---

More complete example below which loads bunch of nodes on cron task which empty taxonomy term references and apply some changes:

/**
 * Implements hook_cron().
 */
function MYMODULE_cron() {
  $query = new EntityFieldQuery();
  $query
    ->entityCondition('entity_type', 'node')
    ->entityCondition('bundle', 'property')
    ->propertyOrderBy('changed', 'DESC')
    ->addTag('type_is_null')
    ->range(0,50); // Maximum of 50.
  $result = $query->execute();

  if (!empty($result['node'])) {
    $nids = array_keys($result['node']);
    $nodes = node_load_multiple($nids);

    foreach ($nodes as $node) {
      // do_some_stuff($node);
    }
  }
}

/**
 * Implements hook_query_TAG_alter()
 */
function MYMODULE_query_type_is_null_alter(QueryAlterableInterface $query) {
  $query->leftJoin('field_data_field_foo', 'f', 'node.nid = f.entity_id AND f.entity_type = :entity_type');
  $query->isNull('f.field_foo_tid'); // Check name by SQL: DESC field_data_field_foo

  $query->leftJoin('field_data_field_bar', 'b', 'node.nid = b.entity_id AND b.entity_type = :entity_type');
  $query->isNull('b.field_bar_tid'); // Check name by SQL: DESC field_data_field_bar
}

Answer 6

You need to wrap Null in quotes.

->fieldCondition('field_name', 'value', 'NULL', '!=');

Answer 7

Please correct me if I'm wrong. It seems that it simply needs to be

$query->fieldCondition('field_name');

to exclude all nodes with an empty field_name field o_O

Tested in Drupal version >= 7.43.