$products = M('product',null,'UXIANG')
->where($map)
->limit($page->firstRow . ',' . $page->listRows)
->order("id desc")
->select();
echo M('product',null,'UXIANG')->getLastSql();
//上面的SQL无法打印出来
M('city')->select();
echo M('city')->getLastSql();
//这里的SQL可以打印出来