Coolest thing in Magento’s is generating your own reports.
The quickest way to create Magento’s reports is to generate them through the grids.
First you will need to create collection of data which you want to display and save.
Then you have to add those fields in your grid, the rest is piece of cake.
In your custom grid class you need to call method “addExportType” from “Mage_Adminhtml_Block_Widget_Grid” class
(your custom grid class needs to extend Mage_Adminhtml_Block_Widget_Grid class).
Code of protected function _prepareColumns() in your Grid class: