diff --git a/src/DynamicEntityReferenceServiceProvider.php b/src/DynamicEntityReferenceServiceProvider.php
index cc6da32..7219157 100644
--- a/src/DynamicEntityReferenceServiceProvider.php
+++ b/src/DynamicEntityReferenceServiceProvider.php
@@ -4,6 +4,10 @@ namespace Drupal\dynamic_entity_reference;
 
 use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Drupal\Core\DependencyInjection\ServiceProviderBase;
+use Drupal\Core\Entity\Query\Sql\QueryFactory as BaseQueryFactory;
+use Drupal\Core\Entity\Query\Sql\pgsql\QueryFactory as BasePgsqlQueryFactory;
+use Drupal\dynamic_entity_reference\Query\PgsqlQueryFactory;
+use Drupal\dynamic_entity_reference\Query\QueryFactory;
 use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Reference;
 
@@ -29,7 +33,25 @@ class DynamicEntityReferenceServiceProvider extends ServiceProviderBase {
       // serializer.normalizer.entity_reference.hal in hal.services.yml.
       $service_definition->addTag('normalizer', ['priority' => 20]);
       $container->setDefinition('serializer.normalizer.entity.dynamic_entity_reference_item.hal', $service_definition);
-
+    }
+    $map = [
+      'entity.query.sql' => [
+        'old' => BaseQueryFactory::class,
+        'new' => QueryFactory::class,
+      ],
+      'pgsql.entity.query.sql' => [
+        'old' => BasePgsqlQueryFactory::class,
+        'new' => PgsqlQueryFactory::class,
+      ]
+    ];
+    foreach ($map as $service_id => $data) {
+      if ($container->hasDefinition($service_id)) {
+        $service_definition = $container->getDefinition($service_id);
+        if ($service_definition->getClass() == $data['old']) {
+          $service_definition->setClass($data['new']);
+          $container->setDefinition($service_id, $service_definition);
+        }
+      }
     }
   }
 
diff --git a/src/Query/PgsqlQueryFactory.php b/src/Query/PgsqlQueryFactory.php
new file mode 100644
index 0000000..57e9994
--- /dev/null
+++ b/src/Query/PgsqlQueryFactory.php
@@ -0,0 +1,9 @@
+<?php
+
+namespace Drupal\dynamic_entity_reference\Query;
+
+use Drupal\Core\Entity\Query\Sql\pgsql\QueryFactory as BaseQueryFactory;
+
+class PgsqlQueryFactory extends BaseQueryFactory {
+
+}
diff --git a/src/Query/QueryFactory.php b/src/Query/QueryFactory.php
new file mode 100644
index 0000000..b50a218
--- /dev/null
+++ b/src/Query/QueryFactory.php
@@ -0,0 +1,9 @@
+<?php
+
+namespace Drupal\dynamic_entity_reference\Query;
+
+use Drupal\Core\Entity\Query\Sql\QueryFactory as BaseQueryFactory;
+
+class QueryFactory extends BaseQueryFactory {
+
+}
diff --git a/src/Query/Tables.php b/src/Query/Tables.php
new file mode 100644
index 0000000..49ecf0e
--- /dev/null
+++ b/src/Query/Tables.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace Drupal\dynamic_entity_reference\Query;
+
+use Drupal\Core\Entity\EntityType;
+use Drupal\Core\Entity\Query\Sql\Tables as BaseTables;
+use Drupal\dynamic_entity_reference\Plugin\Field\FieldType\DynamicEntityReferenceItem;
+
+class Tables extends BaseTables {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function addNextBaseTable(EntityType $entity_type, $table, $sql_column) {
+    // Parent method is overridden in order to choose the correct column to
+    // join on (string or int).
+    $entity_type_id_key = $entity_type->getKey('id');
+    if ($entity_type_id_key !== FALSE) {
+      if (DynamicEntityReferenceItem::entityHasIntegerId($entity_type->id())) {
+        $sql_column .= '_int';
+      }
+    }
+    return parent::addNextBaseTable($entity_type, $table, $sql_column);
+  }
+
+}
diff --git a/tests/src/Kernel/EntityQueryRelationshipTest.php b/tests/src/Kernel/EntityQueryRelationshipTest.php
new file mode 100644
index 0000000..b8ef94a
--- /dev/null
+++ b/tests/src/Kernel/EntityQueryRelationshipTest.php
@@ -0,0 +1,222 @@
+<?php
+
+namespace Drupal\Tests\dynamic_entity_reference\Kernel;
+
+use Drupal\Component\Utility\Unicode;
+use Drupal\Core\Entity\Query\QueryInterface;
+use Drupal\Core\Field\FieldStorageDefinitionInterface;
+use Drupal\entity_test\Entity\EntityTest;
+use Drupal\entity_test\Entity\EntityTestRev;
+use Drupal\entity_test\Entity\EntityTestStringId;
+use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\field\Entity\FieldConfig;
+use Drupal\KernelTests\Core\Entity\EntityKernelTestBase;
+
+/**
+ * Tests dynamic entity reference relationship data.
+ *
+ * @group dynamic_entity_reference
+ */
+class EntityQueryRelationshipTest extends EntityKernelTestBase {
+
+  /**
+   * Modules to install.
+   *
+   * @var array
+   */
+  public static $modules = ['dynamic_entity_reference'];
+
+  /**
+   * The entity type used in this test.
+   *
+   * @var string
+   */
+  protected $entityType = 'entity_test';
+
+  /**
+   * The entity type that is being referenced.
+   *
+   * @var string
+   */
+  protected $referencedEntityType;
+
+  /**
+   * The bundle used in this test.
+   *
+   * @var string
+   */
+  protected $bundle = 'entity_test';
+
+  /**
+   * The name of the field used in this test.
+   *
+   * @var string
+   */
+  protected $fieldName = 'field_test';
+
+  /**
+   * The entity field query factory.
+   *
+   * @var \Drupal\Core\Entity\Query\QueryFactory
+   */
+  protected $factory;
+
+  /**
+   * The results returned by EntityQuery.
+   *
+   * @var array
+   */
+  protected $queryResults;
+
+  /**
+   * The entity_test entities used by the test.
+   *
+   * @var array
+   */
+  protected $entities = [];
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUp() {
+    parent::setUp();
+    $this->factory = \Drupal::service('entity.query');
+  }
+
+  /**
+   * Tests entity query for DER for entites with integer IDs.
+   */
+  public function testEntityQuery() {
+    $this->installEntitySchema('entity_test_rev');
+    $this->referencedEntityType = 'entity_test_rev';
+    $this->setupDerField();
+
+    // Create some test entities which link each other.
+    $referenced_entity_1 = EntityTestRev::create(['name' => 'Foobar']);
+    $referenced_entity_1->save();
+    $referenced_entity_2 = EntityTestRev::create(['name' => 'Barfoo']);
+    $referenced_entity_2->save();
+
+    $entity = EntityTest::create();
+    $entity->field_test[] = $referenced_entity_1;
+    $entity->field_test[] = $referenced_entity_2;
+    $entity->save();
+    $this->assertEquals($entity->field_test[0]->entity->id(), $referenced_entity_1->id());
+    $this->assertEquals($entity->field_test[1]->entity->id(), $referenced_entity_2->id());
+    $this->entities[] = $entity;
+
+    $entity = EntityTest::create();
+    $entity->field_test[] = $referenced_entity_1;
+    $entity->field_test[] = $referenced_entity_2;
+    $entity->save();
+    $this->assertEquals($entity->field_test[0]->entity->id(), $referenced_entity_1->id());
+    $this->assertEquals($entity->field_test[1]->entity->id(), $referenced_entity_2->id());
+    $this->entities[] = $entity;
+    // This returns the 0th entity as that's only one pointing to the 0th
+    // account.
+    $query = $this->factory->get('entity_test')
+      ->condition("field_test.0.entity:entity_test_rev.name", 'Foobar')
+      ->condition("field_test.1.entity:entity_test_rev.name", 'Barfoo');
+    $this->queryResults = $query->execute();
+    $this->assertEquals([1 => 1, 2 => 2], $this->queryResults);
+    $this->assertJoinColumn($query, 'field_test', TRUE);
+  }
+
+  /**
+   * Tests entity query for DER for entities with string IDs.
+   */
+  public function testEntityQueryString() {
+    $this->installEntitySchema('entity_test_string_id');
+    $this->referencedEntityType = 'entity_test_string_id';
+    $this->setupDerField();
+
+    // Create some test entities which link each other.
+    $referenced_entity_1 = EntityTestStringId::create([
+      'name' => 'Foobar',
+      'id' => Unicode::strtolower($this->randomMachineName()),
+    ]);
+    $referenced_entity_1->save();
+    $referenced_entity_2 = EntityTestStringId::create([
+      'name' => 'Barfoo',
+      'id' => Unicode::strtolower($this->randomMachineName()),
+    ]);
+    $referenced_entity_2->save();
+
+    $entity = EntityTest::create();
+    $entity->field_test[] = $referenced_entity_1;
+    $entity->field_test[] = $referenced_entity_2;
+    $entity->save();
+    $this->assertEquals($entity->field_test[0]->entity->id(), $referenced_entity_1->id());
+    $this->assertEquals($entity->field_test[1]->entity->id(), $referenced_entity_2->id());
+    $this->entities[] = $entity;
+
+    $entity = EntityTest::create();
+    $entity->field_test[] = $referenced_entity_1;
+    $entity->field_test[] = $referenced_entity_2;
+    $entity->save();
+    $this->assertEquals($entity->field_test[0]->entity->id(), $referenced_entity_1->id());
+    $this->assertEquals($entity->field_test[1]->entity->id(), $referenced_entity_2->id());
+    $this->entities[] = $entity;
+    // This returns the 0th entity as that's only one pointing to the 0th
+    // account.
+    $query = $this->factory->get('entity_test')
+      ->condition("field_test.0.entity:entity_test_string_id.name", 'Foobar')
+      ->condition("field_test.1.entity:entity_test_string_id.name", 'Barfoo');
+    $this->queryResults = $query->execute();
+    $this->assertEquals([1 => 1, 2 => 2], $this->queryResults);
+    $this->assertJoinColumn($query, 'field_test', FALSE);
+  }
+
+  /**
+   * Helper method to setup the reference field to be tested.
+   */
+  protected function setupDerField() {
+    // Create a field.
+    FieldStorageConfig::create([
+      'field_name' => $this->fieldName,
+      'type' => 'dynamic_entity_reference',
+      'entity_type' => $this->entityType,
+      'cardinality' => FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED,
+      'settings' => [
+        'exclude_entity_types' => FALSE,
+        'entity_type_ids' => [
+          $this->referencedEntityType,
+        ],
+      ],
+    ])->save();
+
+    FieldConfig::create([
+      'field_name' => $this->fieldName,
+      'entity_type' => $this->entityType,
+      'bundle' => $this->bundle,
+      'label' => 'Field test',
+      'settings' => [],
+    ])->save();
+  }
+
+  /**
+   * Helper method to check which column was joined on.
+   *
+   * @param \Drupal\Core\Entity\Query\QueryInterface $query
+   *   The executed query.
+   * @param string $field_name
+   *   The field name being used in the join.
+   * @param bool $integer_column
+   *   TRUE if the expected join column is the `_target_id_int`, FALSE
+   *   otherwise.
+   */
+  protected function assertJoinColumn(QueryInterface $query, $field_name, $integer_column = TRUE) {
+    // @todo Is there a better way than reflection?
+    $reflection = new \ReflectionObject($query);
+    $property = $reflection->getProperty('sqlQuery');
+    $property->setAccessible(TRUE);
+    $sql = (string) $property->getValue($query);
+    if ($integer_column) {
+      $this->assertTrue(strpos($sql, $field_name . '_target_id_int' . "\n") !== FALSE, 'Query joined on target_id_int column.');
+    }
+    else {
+      $this->assertTrue(strpos($sql, $field_name . '_target_id' . "\n") !== FALSE, 'Query joined on target_id column.');
+    }
+  }
+
+}