如下,自己修改一下
Dim ls As new List(Of String())
For Each ary As String() In DataTables("表A").GetValues("id|产品|单号", "id is not null")
Dim sum As Double = DataTables("表A").Compute("sum(数量)", "id = '" & ary(0) & "' and 产品 = '" & ary(1) & "' and 单号 = '" & ary(2) & "'")
Dim arow() As String = {ary(0), ary(1), sum, ary(2)}
ls.Add(arow)
Next
DataTables("表A").DataRows.Clear
For Each l As String() In ls
Dim ndr As DataRow = DataTables("表A").AddNew
ndr("id") = l(0)
ndr("产品") = l(1)
ndr("数量") = l(2)
ndr("单号") = l(3)
Next