I'm trying to migrate users and user profiles to site, where both entities might be already present. In this case I would like to overwrite specified fields and leave others in the original state. I'm trying to map profile_id like this:

    plugin: migration_lookup
    no_stub: true
    # previous user migration
    migration: mayors_users
    # property in the source data
    source: lau
    plugin: entity_lookup
    entity_type: profile
    bundle: profile
    bundle_key: type
    value_key: uid
    source: '@uid'

However, this fails, so profile_id is null.

Do you happen to know, how can I use entity_lookup (or another) plugin for this?

EDIT: It looks like this might be a Drupal Core issue. I debugged the code of EntityLookup.php plugin and printed the actual DB query generated from the entity query:

SELECT base_table.revision_id AS revision_id, base_table.profile_id AS profile_id
FROM profile base_table
         INNER JOIN profile profile ON profile.profile_id = base_table.profile_id
WHERE (profile.uid = '153')
  AND (profile.type = 'profile')

This works fine and return following result when used directly against MySQL server:

revision_id profile_id
87 87

However, $query->execute() still returns an empty array. Why?

EDIT: It looks like this might be a bug: https://www.drupal.org/project/migrate_plus/issues/3230477

2 Answers 2


If I understand your question correctly and it is indeed a bug (so that there is no proper solution to your problem) I can think of at least 2 ways you could work around this.

1. hook_migrate_prepare_row / hook_migrate_MIGRATION_ID_prepare_row

You could use hook_migrate_prepare_row or hook_migrate_MIGRATION_ID_prepare_row to preprocess your source data and fetch the uid and profile id manually, something like this:

 * Implements hook_migrate_MIGRATE_ID_prepare_row().
function my_module_migrate_MIGRATE_ID_prepare_row(Row $row, MigrateSourceInterface $source, MigrationInterface $migration) {
  $raw_data = (object) $row->getSource()['raw'];
  // Here the database queries as needed.
  // $uid = \Drupal::database()->select ...
  // $profile_id = \Drupal::database()->select ...
  $row->setSourceProperty('uid', $uid);
  $row->setSourceProperty('profile_id', $profile_id);

Note that Migrate Plus provides an object-oriented alternative to those hooks: https://www.drupal.org/docs/upgrading-drupal/customize-migrations-when-upgrading-to-drupal-8-or-later#s-migrate-plus-provides-a-prepare-row-event

2. Write your own process plugin

There is good documentation on how to write a process plugin on drupal.org: https://www.drupal.org/docs/8/api/migrate-api/migrate-process/writing-a-process-plugin

It basically looks like this:


namespace Drupal\my_module\Plugin\migrate\process;

use Drupal\migrate\ProcessPluginBase;
use Drupal\migrate\MigrateExecutableInterface;
use Drupal\migrate\Row;

 * Provides a 'ExtractProfileIdFromLau' migrate process plugin.
 * @MigrateProcessPlugin(
 *  id = "extract_profile_id_from_lau"
 * )
class ExtractProfileIdFromLau extends ProcessPluginBase {

   * {@inheritdoc}
  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
    // Fetch profile id.
    $profile_id = \Drupal::database()->select ...
    return $profile_id;


And it can be referenced in your migration.yml file under the process section, something like this for example:

      plugin: extract_profile_id_from_lau
      source: lau

Not quite sure which way would work best for you, but those are the 2 ideas that would come to mind. At least that's how I would try it.


In the end, the solution was creating my own migration process plugin, the key part of which is:

$statement = \Drupal::database()
  ->select('profile', 'p')
  ->fields('p', ['profile_id'])
  ->condition('p.uid', $value, '0')
$result = $statement->fetchAllAssoc('profile_id');
return array_keys($result)[0];

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