主题：[求助]我这样写了个统计代码，不知对不对？

Dim bd1 As New SQLGroupTableBuilder("报主清单","长期医嘱")
Dim dt1 As fxDataSource
bd1.Groups.AddDef("收费项目") '根据品名分组
bd1.Groups.AddDef("项目类别") '根据型号分组
bd1.Groups.AddDef("项目规格") '根据品名分组
bd1.Groups.AddDef("单位") '根据型号分组
bd1.Groups.AddDef("单价") '根据型号分组
bd1.Totals.AddExp("长期医嘱_报数","IIF([数量] >= 0,IsNull([数量] * [片数] * [次数],0),0)") '对数量进行统计
bd1.Totals.AddExp("长期医嘱_金额","[报数] * [单价]") '对数量进行统计
dt1 = bd1.BuildDataSource()

Dim bd2 As New SQLGroupTableBuilder("统计表2","临时医嘱")
Dim dt2 As fxDataSource
bd2.Groups.AddDef("收费项目") '根据品名分组
bd2.Groups.AddDef("项目类别") '根据型号分组
bd2.Groups.AddDef("项目规格") '根据品名分组
bd2.Groups.AddDef("单位") '根据型号分组
bd2.Groups.AddDef("单价") '根据型号分组
bd2.Totals.AddExp("临时医嘱_报数","IIF([开始日期] >= [报起始日期]And[开始日期] <= [报截止日期],IsNull([数量],0),0)") '对数量进行统计
bd2.Totals.AddExp("临时医嘱_金额","[报数] * [单价]") '对数量进行统计
dt2 = bd2.BuildDataSource()

Dim nms As String() = {"收费项目","项目类别","项目规格","单位","单价"}
dt1.Combine(nms,dt2,nms)'将销售统计数据组合到进货统计数据

Tables("窗口1_Table1").DataSource = dt1 '将统计结果绑定到Table

With DataTables("窗口1_Table1").DataCols  '用表达式列计算库存数据
    .Add("数量",Gettype(Integer), "IsNull([长期医嘱_报数],0) + ISNULL([临时医嘱_报数],0)")
    .Add("金额",Gettype(Double), "IsNull([长期医嘱_金额],0) + ISNULL([临时医嘱_金额],0)")
End With