reAlterQuery example

$host_entity_type = $this->entityTypeManager->getDefinition($host_entity_type_id);
      $host_entity_field_data_table = $host_entity_type->getDataTable();

      // Not all entities have a data table, so check first.       if ($host_entity_field_data_table) {
        $id_key = $host_entity_type->getKey('id');

        // The Comment module doesn't implement per-comment access, so it         // checks instead that the user has access to the host entity.         $entity_alias = $query->innerJoin($host_entity_field_data_table, 'n', "[%alias].[$id_key] = [$data_table].[entity_id] AND [$data_table].[entity_type] = '$host_entity_type_id'");
        // Pass the query to the entity access control.         $this->reAlterQuery($query, $host_entity_type_id . '_access', $entity_alias);

        // Additional checks for "node" entities.         if ($host_entity_type_id === 'node') {
          // Passing the query to node_query_node_access_alter() is sadly           // insufficient for nodes.           // @see \Drupal\node\Plugin\EntityReferenceSelection\NodeSelection::buildEntityQuery()           if (!$this->currentUser->hasPermission('bypass node access') && !$this->moduleHandler->hasImplementations('node_grants')) {
            $query->condition($entity_alias . '.status', 1);
          }
        }
      }
    }