Duplicate Flagged Nodes in View

How many flags do you have? Did you filter by them?

(BTW: please don't use random tags!)

Can you post the config output of your view please?

The duplicates appear when "Any user" is chosen in flag relationship settings for "By" option. If "Current user" chosen, duplicates don't appear though you can't get total flags count then.

Thanks for the explanation!

In which case, this is as designed. If you join nodes to flaggings, and the flag is non-global, then you will get repeated rows because there will be more than one flagging for each node.

Then we should allow to join on flag_counts table.
Now user can use flagging relationship and it would work with DISTINCT if the view wouldn't add {flagging}.id field (which is not used) to the query.

Shortly, the following case should be available: output a list of entities with total number of flags (of one type) on it. E.g. you want to make a list of popular nodes and show how many users flagged it.

> E.g. you want to make a list of popular nodes and show how many users flagged it.
Yep - exactly the use case I'm aiming for.
Happy to try write a patch, if some advice can be given as to where to start

> Happy to try write a patch, if some advice can be given as to where to start

> Then we should allow to join on flag_counts table.

That sounds like the right approach. Though I've a feeling there is already an issue for this -- please check before uploading a patch to this one!

The steps would be:

- find where we declared Views data. Might be the hook, or might be an entity views data handler for the flagging entity
- declare flag_counts table if not already done
- iterate over all flags
- for each different entity type that has a flag on it, add a relationship to that entity type's base table that joins to flag_counts on the entity ID and entity type (the entity type needs to be in a join extra property in the views data)
- add a views relationship handler plugin, which has:
-- setting for to let you pick the flag
-- query() method which restricts the join by the flag
- add a field to the flag_counts table for the count

Hey, I just wanted to share a workaround I did for our site. Inside a custom module I added an implementation of hook_views_query_alter() with a group by like this:

use Drupal\views\ViewExecutable;
use Drupal\views\Plugin\views\query\QueryPluginBase;

/**
 * Implements hook_views_query_alter().
 */
function YOURMODULE_views_query_alter(ViewExecutable $view, QueryPluginBase $query) {
  if ($view->id() == 'YOURVIEWID' && $view->current_display == 'YOURDISPLAY') {
    $query->addField('node', 'nid', 'node_nid', array('function' => 'groupby'));
    $query->addGroupBy('node.nid');
  }
}

Any news about this issue?

@attheshow, thanks for sharing

I took attheshow's idea and created a hook_views_query_alter implementation in the flag.module file itself that applies that group by to the base_table.base_field for the view whenever a flag relationship is present and the count is being output.

It's possible this could use some refinement, but here's the patch:

Patch #13 works and fixes the issue. Thank you

Is there anyone who could get this patch in next release?

+++ b/flag.module
@@ -115,6 +116,18 @@ function flag_help($route_name, RouteMatchInterface $route_match) {
+  if (!empty($view->relationship) && is_array($view->relationship) && isset($view->relationship['flag_relationship']) && isset($view->field['count'])) {

We're testing for a relationship handler that we provide.

So we should be able to make this query alteration in the handler itself, rather than use a hook.

Thank you for the info. I hope this gets forward soon :)

+1 rtbc for patch #13 on 8.x-4.0-alpha3

Please see my comment in #17 -- the patch needs work.

I have the same "duplicates" issue using a flag called "Follow" on a single node type, to sort by "most followed" descending. I tried the patch in #17, but it did not result in the desired outcome. The solution in #10 did, however, provide the desired outcome. Thanks, @attheshow!

We can use unique index. It will resolve the bug

function hook_update_8701() {
  // Remove duplicates to avoid exception during creating unique index.
  /** @var \Drupal\flag\Entity\Storage\FlaggingStorageInterface $flagging_storage */
  $flagging_storage = Drupal::entityTypeManager()->getStorage('flagging');
  $flaggings_values = $flagging_storage->getAggregateQuery()
    ->groupBy('id')
    ->groupBy('uid')
    ->groupBy('entity_id')
    ->groupBy('flag_id')
    ->execute();

  $exists_flaggings = [];
  foreach ($flaggings_values as $flagging_values) {
    $key = $flagging_values['uid'] . $flagging_values['entity_id'] . $flagging_values['flag_id'];
    if (isset($exists_flaggings[$key])) {
      $flagging_storage->load($flagging_values['id'])->delete();
    }
    else {
      $exists_flaggings[$key] = $key;
    }
  }

  if (Drupal::database()->schema()->indexExists('flagging', 'unique_flag')) {
    Drupal::database()->schema()->dropIndex('flagging', 'unique_flag');
  }
  Drupal::database()->query(
    'ALTER TABLE `flagging` ADD UNIQUE `unique_flag` (`uid`, `flag_id`(30), `entity_id`(40)) USING BTREE;'
  );
}

Greetings, the patch given above is not working. How can I solve this problem?

Patch isn't working on my end anymore. Any updates?

@attheshow's solution on #10 does work for me as a custom module. Can we not get this as a workable patch? Seems as though #13 isn't cutting it?

Maybe I'm missing something obvious, but I solved this problem by just enabling "Use aggregation" in the advanced settings of the view. That way I only get one row per node and still can query the flag count.

This does not work with content types with images due to a bug in views, and could also be considered a workaround, not a solution.

I used https://www.drupal.org/project/issues/views_distinct to solve that problem (filtering by NID). You'll need to patch it to get a D9/10 version though.