Creating a Gridview and Charts with Main Query

I'm trying to create different Charts with only one query, the one that I use to present it on the Gridview. The problem is that I have to divide the content of the DataTable in different columns and then have count them or make a sum from different columns. How can I do this. This is my code for creating the Report and a function that I will call to make the charts. The Chart function in a past version of the program was made with different queries but some times it created discrepancy on the Data Showned on the DataView and the Data presented on the Charts. First of all I will like to know how can I divide all the DataTable in different DataColumns so then I can manipulate them.

protected void BuildReport()
    {
        try
        {
            dbconn oraconn = new dbconn(dbname);

   &nb ...