Index: class.ux_t3lib_db.php
===================================================================
--- class.ux_t3lib_db.php	(revision 28572)
+++ class.ux_t3lib_db.php	(working copy)
@@ -1040,10 +1040,10 @@
 	 */
 	protected function _quoteFieldNames(array $select_fields) {
 		foreach ($select_fields as $k => $v) {
-			if ($select_fields[$k]['field'] != '' && $select_fields[$k]['field'] != '*') {
+			if ($select_fields[$k]['field'] != '' && $select_fields[$k]['field'] != '*' && !is_numeric($select_fields[$k]['field'])) {
 				$select_fields[$k]['field'] = $this->quoteName($select_fields[$k]['field']);
 			}
-			if ($select_fields[$k]['table'] != '') {
+			if ($select_fields[$k]['table'] != '' && !is_numeric($select_fields[$k]['table'])) {
 				$select_fields[$k]['table'] = $this->quoteName($select_fields[$k]['table']);
 			}
 			if ($select_fields[$k]['as'] != '') {
Index: tests/db_oracle_testcase.php
===================================================================
--- tests/db_oracle_testcase.php	(revision 28564)
+++ tests/db_oracle_testcase.php	(working copy)
@@ -253,6 +253,20 @@
 		$this->assertEquals($expected, $query);
 	}
 
+	/**
+	 * @test
+	 * http://bugs.typo3.org/view.php?id=13422
+	 */
+	public function numericColumnsAreNotQuoted() {
+		$query = $this->cleanSql($GLOBALS['TYPO3_DB']->SELECTquery(
+			'1',
+			'be_users',
+			'username = \'_cli_scheduler\' AND admin = 0 AND be_users.deleted = 0'
+		));
+		$expected = 'SELECT 1 FROM "be_users" WHERE "username" = \'_cli_scheduler\' AND "admin" = 0 AND "be_users"."deleted" = 0';
+		$this->assertEquals($expected, $query);
+	}
+
 	///////////////////////////////////////
 	// Tests concerning remapping
 	///////////////////////////////////////