How to make charts from database data

Hi, here is another way that you can try:

DataTable table = ...
 
var ef = new ExcelFile();
var ws = ef.Worksheets.Add("Sheet");
 
ws.InsertDataTable(table);
var chart = ws.Charts.Add(ChartType.Line, "A6", "F15");
chart.SelectData(ws.GetUsedCellRange(true), false, true, true);
 
ef.Save("Sample.xlsx");

Code comes from this article about creating an excel chart element in C#.

I think the first thing that you need is to export your database table to excel and then, generate pie chart or line chart in excel. Here, I think it is necessary to introduce this free libary. it can export data to excel and generate 15 types of charts such as pie chart, column chart, line chart, Radar, surface etc, you can see details here: http://exportdata.codeplex.com
since the code is too long, I only show you a part of  pie chart code:
chart1.CategoryLabels.ColX = ((System.Byte)(1));
chart1.CategoryLabels.ColY = ((System.Byte)(1));
chart1.CategoryLabels.RowX = 1;
chart1.CategoryLabels.RowY = 9;
chart1.CategoryLabelsColumn = "Name";
 chart1.DataRangeSheet = "charts";
chart1.Position.AutoPosition.Height = 12;
 chart1.Position.AutoPosition.Top = 1;
 chart1.Position.AutoPosition.Width = 6;
chartSeries1.DataColumn = "Population";
chartSeries1.DataRangeSheet = "charts";
chartSeries1.Title = "Population";
chart1.Series.Add(chartSeries1);
chart1.Style = Spire.DataExport.XLS.ChartStyle.Pie3d;
chart1.Title = "Chart demo";
workSheet3.Charts.Add(chart1);
You can know more detail here:

Export to Excel and Create Pie Chart