diff --git a/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/Comment.php b/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/Comment.php
index cb93447..ec93709 100644
--- a/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/Comment.php
+++ b/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/Comment.php
@@ -33,16 +33,15 @@ public function entityFieldQueryAlter(SelectInterface $query) {
     // Adding the 'comment_access' tag is sadly insufficient for comments: core
     // requires us to also know about the concept of 'published' and
     // 'unpublished'.
+    $tables = $query->getTables();
+    $base_table = $tables['base_table']['alias'];
     if (!user_access('administer comments')) {
-      $tables = $query->getTables();
-      $query->condition(key($tables) . '.status', COMMENT_PUBLISHED);
+      $query->condition("$base_table.status", COMMENT_PUBLISHED);
     }
 
     // The Comment module doesn't implement any proper comment access,
     // and as a consequence doesn't make sure that comments cannot be viewed
     // when the user doesn't have access to the node.
-    $tables = $query->getTables();
-    $base_table = key($tables);
     $node_alias = $query->innerJoin('node', 'n', '%alias.nid = ' . $base_table . '.nid');
     // Pass the query to the node access control.
     $this->reAlterQuery($query, 'node_access', $node_alias);
diff --git a/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/File.php b/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/File.php
index 05e62ef..858645c 100644
--- a/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/File.php
+++ b/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/File.php
@@ -32,7 +32,7 @@ class File extends SelectionGeneric {
   public function entityFieldQueryAlter(SelectInterface $query) {
     // Core forces us to know about 'permanent' vs. 'temporary' files.
     $tables = $query->getTables();
-    $base_table = key($tables);
+    $base_table = $tables['base_table']['alias'];
     $query->condition('status', FILE_STATUS_PERMANENT);
 
     // Access control to files is a very difficult business. For now, we are not
diff --git a/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/Node.php b/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/Node.php
index dc97ff0..b5dd021 100644
--- a/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/Node.php
+++ b/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/Node.php
@@ -37,7 +37,8 @@ public function entityFieldQueryAlter(SelectInterface $query) {
     // it is supposed to handle this check.
     if (!user_access('bypass node access') && !count(module_implements('node_grants'))) {
       $tables = $query->getTables();
-      $query->condition(key($tables) . '.status', NODE_PUBLISHED);
+      $base_table = $tables['base_table']['alias'];
+      $query->condition("$base_table.status", NODE_PUBLISHED);
     }
   }
 }
diff --git a/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/Term.php b/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/Term.php
index 6fe925e..7b8cbc8 100644
--- a/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/Term.php
+++ b/core/modules/field/modules/entity_reference/lib/Drupal/entity_reference/Plugin/entity_reference/selection/Term.php
@@ -34,7 +34,7 @@ public function entityFieldQueryAlter(SelectInterface $query) {
     // and as a consequence doesn't make sure that taxonomy terms cannot be
     // viewed when the user doesn't have access to the vocabulary.
     $tables = $query->getTables();
-    $base_table = key($tables);
+    $base_table = $tables['base_table']['alias'];
     $vocabulary_alias = $query->innerJoin('taxonomy_vocabulary', 'n', '%alias.vid = ' . $base_table . '.vid');
     $query->addMetadata('base_table', $vocabulary_alias);
     // Pass the query to the taxonomy access control.