diff --git a/core/lib/Drupal/Core/Entity/Query/QueryInterface.php b/core/lib/Drupal/Core/Entity/Query/QueryInterface.php
index caadc37..479fbac 100644
--- a/core/lib/Drupal/Core/Entity/Query/QueryInterface.php
+++ b/core/lib/Drupal/Core/Entity/Query/QueryInterface.php
@@ -52,6 +52,17 @@ public function getEntityTypeId();
    *   "tags" "is the same as "tags.value" as value is the default column.
    *   If two or more conditions have the same field names they apply to the
    *   same delta within that field.
+   *   It is also possible to add the numeric delta value between the field
+   *   name and the column name, for example tags.5.value.
+   *   Finally, it's possible to create a condition on delta itself by using a
+   *   ? as a wildcard. For example, ->condition('tags.?', 5) will find only
+   *   entities which have at least six tags. Also, tags.? within a condition
+   *   group means a specific delta so
+   * @code
+   *   ->condition('tags.?', 0, '>'))
+   *   ->condition('tags.?.value', 'foo'))
+   * @endcode
+   *   will only find the "foo" tag if it is not the first tag.
    * @param $value
    *   The value for $field. In most cases, this is a scalar and it's treated as
    *   case-insensitive. For more complex options, it is an array. The meaning
diff --git a/core/lib/Drupal/Core/Entity/Query/Sql/Tables.php b/core/lib/Drupal/Core/Entity/Query/Sql/Tables.php
index e0fbe85..4c214f0 100644
--- a/core/lib/Drupal/Core/Entity/Query/Sql/Tables.php
+++ b/core/lib/Drupal/Core/Entity/Query/Sql/Tables.php
@@ -125,15 +125,17 @@ public function addField($field, $type, $langcode) {
           }
           // Is this a delta wildcard?
           elseif ($next == '?') {
-            $index_prefix .= ".$delta";
+            $index_prefix .= '.?';
             // Do not process it again.
             $key++;
-            // Is this a real condition with a wildcard?
+            // If there are yet specifiers to work with then continue
+            // processing. If this is the last specifier then use the delta
+            // wildcard as column name.
             if ($key < $count) {
               $next = $specifiers[$key + 1];
             }
             else {
-              $column = $next;
+              $column = '?';
             }
           }
           // Is this a field column?
diff --git a/core/lib/Drupal/Core/Entity/Query/Sql/TablesInterface.php b/core/lib/Drupal/Core/Entity/Query/Sql/TablesInterface.php
index ac6d986..13745a4 100644
--- a/core/lib/Drupal/Core/Entity/Query/Sql/TablesInterface.php
+++ b/core/lib/Drupal/Core/Entity/Query/Sql/TablesInterface.php
@@ -16,8 +16,10 @@
    * Adds a field to a database query.
    *
    * @param string $field
-   *   If it contains a dot, then field name dot field column or field name dot
-   *   delta dot field column. If it doesn't then entity property name.
+   *   If it doesn't contain a dot, then an entity base field name.
+   *   If it contains a dot, then either field name dot field column or
+   *   field name dot delta dot field column. Delta can be a numeric value or a
+   *   ? for any value.
    * @param string $type
    *   Join type, can either be INNER or LEFT.
    * @param $langcode