谢谢楼上,我明白错在哪了,正确的(没用窗口表):
Dim bd1 As New GroupTableBuilder("统计表1",DataTables("进货单"))
Dim dt1 As fxDataSource
bd1.Groups.AddDef("日期","月份")
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("日期","月份")
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("日期","月份")
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()
Dim nms As String() = {"月份","型号"} '指定连接列
dt1.Combine(nms,dt2,nms) '将销售统计数据组合到进货统计数据
dt1.Combine(nms,dt3,nms) '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
With DataTables("统计表1").DataCols '用表达式列计算库存数据
.Add("库存_数量",Gettype(Integer), "IsNull([进货_数量],0) - ISNULL([销售_数量],0) - ISNULL([退货_数量],0)")
.Add("库存_金额",Gettype(Double), "[库存_数量] /[进货_数量] * [进货_金额]")
End With
MainTable=Tables("统计表1")