[Zope] What's Wrong ? ZMySQLDB, insert Ok, select Empty!

I just installed a "MySQL connection" in Zope. Then add a "SQL Method" to insert data into a table named "staff" in MySQL, and succeccfully inserted several entries. I have checked it by mysql (a client program of MySQL). My problem is : I created another "SQL Method" which do "select" from database. The sql command is very simple "select * from staff". I gain nothing back throught this "SQL Method". I have granted "select" right to the username which was used to make connection. No error messages, just "There was no data matching this y2fun (connected) query. " Any suggestions? Thanks a lot. Iap, Singuan iap@y2fun.com http://y2fun.com