Index: /hadoop-register/check_activate_code.php
===================================================================
--- /hadoop-register/check_activate_code.php	(revision 108)
+++ /hadoop-register/check_activate_code.php	(revision 109)
@@ -34,5 +34,5 @@
       $str = sprintf("SELECT `hadoop_user` , `hadoop_password` 
 		      FROM `%s` 
-		      WHERE `hadoop_owner` LIKE '' 
+		      WHERE `hadoop_owner` IS NULL 
 		      LIMIT 1 ",$mysql_table_owner );
       $result = mysql_query($str, $link) or die(mysql_error() );