diff --git a/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php b/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php
index 620b82911ee7fb875514d83fb2bd792836fef1df..66cd34fafacdfc362d748328910a435146564964 100644
--- a/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php
+++ b/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php
@@ -140,7 +140,7 @@ public function queryRange($query, $from, $count, array $args = array(), array $
 
   public function queryTemporary($query, array $args = array(), array $options = array()) {
     $tablename = $this->generateTemporaryTableName();
-    $this->query(preg_replace('/^SELECT/i', 'CREATE TEMPORARY TABLE {' . $tablename . '} Engine=MEMORY SELECT', $query), $args, $options);
+    $this->query('CREATE TEMPORARY TABLE {' . $tablename . '} Engine=MEMORY ' . $query, $args, $options);
     return $tablename;
   }
 
diff --git a/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php b/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
index 8c2a34aa1f9aba2d6b8ea5028ae2f14c61ded083..cb8e5010463eb548df2d69368ec54dbfb17d0ecf 100644
--- a/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
@@ -179,7 +179,7 @@ public function queryRange($query, $from, $count, array $args = array(), array $
 
   public function queryTemporary($query, array $args = array(), array $options = array()) {
     $tablename = $this->generateTemporaryTableName();
-    $this->query(preg_replace('/^SELECT/i', 'CREATE TEMPORARY TABLE {' . $tablename . '} AS SELECT', $query), $args, $options);
+    $this->query('CREATE TEMPORARY TABLE {' . $tablename . '} AS ' . $query, $args, $options);
     return $tablename;
   }
 
diff --git a/core/lib/Drupal/Core/Database/Driver/sqlite/Connection.php b/core/lib/Drupal/Core/Database/Driver/sqlite/Connection.php
index 137e23c1ea9254838517c2f2c46725e07a10cf8d..2031e4b9249697fb5e59f412456580e2ab593224 100644
--- a/core/lib/Drupal/Core/Database/Driver/sqlite/Connection.php
+++ b/core/lib/Drupal/Core/Database/Driver/sqlite/Connection.php
@@ -266,7 +266,7 @@ public function queryTemporary($query, array $args = array(), array $options = a
     $prefixes[$tablename] = '';
     $this->setPrefix($prefixes);
 
-    $this->query(preg_replace('/^SELECT/i', 'CREATE TEMPORARY TABLE ' . $tablename . ' AS SELECT', $query), $args, $options);
+    $this->query('CREATE TEMPORARY TABLE ' . $tablename . ' AS ' . $query, $args, $options);
     return $tablename;
   }
 
diff --git a/core/modules/system/lib/Drupal/system/Tests/Database/TemporaryQueryTest.php b/core/modules/system/lib/Drupal/system/Tests/Database/TemporaryQueryTest.php
index ea61cd90edf2a1ee73acdd258be6f892533866ad..c57d58751e3fa040d9f7105e4719854b093b2e6d 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Database/TemporaryQueryTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Database/TemporaryQueryTest.php
@@ -54,5 +54,14 @@ function testTemporaryQuery() {
 
     $this->assertEqual($this->countTableRows($table_name_test), $this->countTableRows('test'), 'A temporary table was created successfully in this request.');
     $this->assertEqual($this->countTableRows($table_name_task), $this->countTableRows('test_task'), 'A second temporary table was created successfully in this request.');
+
+    // Check that leading whitespace and comments do not cause problems
+    // in the modified query.
+    $sql = "
+      -- Let's select some rows into a temporary table
+      SELECT name FROM {test}
+    ";
+    $table_name_test = db_query_temporary($sql, array());
+    $this->assertEqual($this->countTableRows($table_name_test), $this->countTableRows('test'), 'Leading white space and comments do not interfere with temporary table creation.');
   }
 }