主题：求教关于油耗平均值的算法

Dim g As New GroupTableBuilder("统计表2", DataTables("表A"))
g.Groups.AddDef("材料名称")
g.Groups.AddDef("车型")
g.Groups.AddDef("车号")
g.Groups.AddDef("加油日期", DateGroupEnum.Year, "年")
g.Totals.AddDef("数量")
g.Totals.AddDef("单次里程统计")
g.Build()
DataTables("统计表2").DataCols.Add("单次平均油耗/k", Gettype(Double), "数量/单次里程统计")
MainTable = Tables("统计表2")

Dim nf As WinForm.ComboBox = e.Form.Controls("输入年份")
Dim cx As WinForm.ComboBox = e.Form.Controls("输入车型")
'--------------生成统计表----------------

Dim g As New GroupTableBuilder("统计表2", DataTables("表A"))
g.Groups.AddDef("材料名称")
g.Groups.AddDef("车型")
g.Groups.AddDef("车号")
g.Groups.AddDef("加油日期", DateGroupEnum.Year, "年")
g.Totals.AddDef("数量")
g.Totals.AddDef("单次里程统计")
If cx.Text > "" AndAlso nf.value > "" AndAlso cx.Text <> "请输入车型" AndAlso nf.Text <> "请输入年份" Then
    g.Filter = "[车型] = '" & cx.value & "' And [加油日期] >= #" & new Date(nf.value, 1, 1) & "# And  [加油日期]<= #" & new Date(nf.value, 12, 31) & "#"   '动态表达式没有加单引号
End If
g.Build()
DataTables("统计表2").DataCols.Add("单次平均油耗", Gettype(Double), "Convert(数量/单次里程统计 * 100, 'System.Int64') / 100 ", "单次平均油耗/K")
MainTable = Tables("统计表2")
'----------------生成图表--------------
Dim Chart As WinForm.Chart '定义一个图表变量
Dim Series As WinForm.ChartSeries '定义一个图系变量
Dim t As Table = Tables("统计表2") '定义一个变量t引用数据表
Chart = e.Form.Controls("Chart1") ' 引用窗口中的图表
Chart.ChartType = ChartTypeEnum.Bar '图表类型该为Bar(条形)
Chart.DataSource = "统计表2" '设置绑定表
Chart.SeriesList.Clear() '清除图表原来的图系
Series = Chart.SeriesList.Add() '增加一个图系
Series.X.DataField = "车号" 'X轴绑定到产品列
Series.Y.DataField = "单次平均油耗" 'Y轴绑定到数量列
Chart.AxisY.AnnoFormatString = "0.00"
Series.DataLabelText = "{#YVAL}"

参考示例1

http://www.foxtable.com/help/topics/0605.htm