主题：[求助]如何根据日期显示组合统计

Dim bd1 As New GroupTableBuilder("统计表1",DataTables("进货单"))
Dim dt1 As fxDataSource
bd1.Groups.AddDef("型号") '根据型号分组
bd1.Totals.AddDef("数量","进货_数量") '对数量进行统计
bd1.Totals.AddDef("金额","进货_金额") '对金额进行统计
dt1 = bd1.BuildDataSource() 

Dim bd2 As New GroupTableBuilder("统计表2",DataTables("销售单"))
Dim dt2  As fxDataSource
bd2.Groups.AddDef("型号") '根据型号分组
bd2.Totals.AddDef("数量","销售_数量") '对数量进行统计
bd2.Totals.AddDef("金额","销售_金额") '对金额进行统计
dt2 = bd2.BuildDataSource()

Dim bd3 As New GroupTableBuilder("统计表3",DataTables("退货单"))
Dim dt3 As fxDataSource
bd3.Groups.AddDef("型号") '根据型号分组
bd3.Totals.AddDef("数量","退货_数量") '对数量进行统计
bd3.Totals.AddDef("金额","退货_金额") '对金额进行统计
dt3 = bd3.BuildDataSource()

dt1.Combine("型号",dt2,"型号") '将销售统计数据组合到进货统计数据
dt1.Combine("型号",dt3,"型号") '将退货统计数据组合到进货统计数据
dt1.Show("统计表1") '显示统计结果