IDinWinGs

I have trouble in modifying PHPExcel library. I have search through Google and search option here. But i cannot found the solution. I have successful in export all the column from my table into Excel. But the problem now is I want export only selected column to Excel file. Example : I have 3 checkbox (A,B,C) equivalent with column (A,B,C) from my database table . I want to export only column A so that I check only checkbox A. If I want export column B & C then I will check the checkbox B & C. I hope you guys can help me with this. Thank you !