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I have a database like this:
T0 T1 T2
main_1 subcategory_1 Reason_1
main_2 subcategory_2 Reason_2
main_3 subcategory_3 Reason_3
main_4 subcategory_4 Reason_4
main_5 subcategory_2 Reason_4
main_1 subcategory_3 Reason_3
main_2 subcategory_2 Reason_2
main_1 subcategory_3 Reason_2
main_2 subcategory_3 Reason_3


I want to draw a pie chart for main_1 total subcategories are there. also draw a pie chart for Main_1 -> subcategory_1 for total reasons are there

What I have tried:

I had tried with

foreach (var item in Selected_TABLENAME)
                       {

                           if (item.Contains("All_Red_Events"))
                           {

                               foreach(var iteam1 in EventCategories)
                               {
                                   foreach(var iteam2 in SubEventCategories)
                                   {
                                           OleDbCommand cmd6 = new OleDbCommand();
                                           OleDbDataReader reader2 = null;
                                           cmd6 = new OleDbCommand("select  [T2] FROM " + item.ToString() + " WHERE ( [T0]='" + iteam1.ToString() + "'" +" and" + " [T1]='" + iteam2.ToString() + "')" + "", connection2);
                                           reader2 = cmd6.ExecuteReader();

                                           while (reader2.Read())
                                           {

                                               Subcategoriesreason.Add(reader2["T0"].ToString());
                                           }
                                   }
                               }
                            }

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