Index: wp-includes/wp-db.php
===================================================================
--- wp-includes/wp-db.php	(revision 29938)
+++ wp-includes/wp-db.php	(working copy)
@@ -1869,7 +1869,7 @@
 		}
 
 		// If there is a value return it else return null
-		return ( isset( $values[$x] ) && $values[$x] !== '' ) ? $values[$x] : null;
+		return isset( $values[$x] ) ? $values[$x] : null;
 	}
 
 	/**