Discuz! info: MySQL Query Error

Time: 2012-1-28 3:43pm
Script: /index.php

SQL: UPDATE cdb_stats SET count=count+1 WHERE (type='total' AND var='hits') OR (type='browser' AND var='Other') OR (type='os' AND var='Other') OR (type='total' AND var='guests') OR (type='month' AND var='201201') OR (type='week' AND var='6') OR (type='hour' AND var='15')
Error: No database selected
Errno.: 1046

Similar error report has beed dispatched to administrator before.