diff --git a/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php b/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php
index 128780f..b8122d9 100644
--- a/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php
+++ b/core/lib/Drupal/Core/Database/Driver/mysql/Connection.php
@@ -109,7 +109,7 @@ class Connection extends DatabaseConnection {
 
   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 4fd7d0d..df561d7 100644
--- a/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Connection.php
@@ -168,7 +168,7 @@ class Connection extends DatabaseConnection {
 
   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 abda556..08e2986 100644
--- a/core/lib/Drupal/Core/Database/Driver/sqlite/Connection.php
+++ b/core/lib/Drupal/Core/Database/Driver/sqlite/Connection.php
@@ -262,7 +262,7 @@ class Connection extends DatabaseConnection {
     $prefixes[$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 529e218..39e68df 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.');
   }
 }