Fixed an AR_caching error where it wasn't tracking table aliases (#3463)
diff --git a/system/database/drivers/mysql/mysql_driver.php b/system/database/drivers/mysql/mysql_driver.php
index edf09a1..2bc66ec 100644
--- a/system/database/drivers/mysql/mysql_driver.php
+++ b/system/database/drivers/mysql/mysql_driver.php
@@ -471,7 +471,7 @@
 			return "`{$item}`";

 		}

 

-		$exceptions = array('AS', '/', '-', '%', '+', '*');

+		$exceptions = array('AS', '/', '-', '%', '+', '*', 'OR', 'IS');

 		

 		foreach ($exceptions as $exception)

 		{