For Each ary() As String In DataTables("产品供应商").GetValues("品名|供应商") Dim filter As String = "品名='" & ary(0) & "' And 供应商='" & ary(1) & "'" Dim sum As Double = DataTables("产品供应商").Compute("Sum(日均销量)",filter) If sum > 0 Then For Each dr1 As DataRow In DataTables("产品供应商").Select(filter) dr1("标准库存天数") = dr1("供应商起订量") / sum Next End If Next