主题：一个很棘手的数据表转换问题

确实很容易：

Dim nms() As String = {"第三列","第四列","第五列","第六列","第七列","第八列","第九列","第十一列","第十二列","第十三列","第十四列","第十五列"}
For Each dr As DataRow In DataTables("运动项目报名表").DataRows
    For Each nm As String In nms
        If dr.IsNull(nm)  = False
            Dim r As Row = Tables("运动员比赛表").AddNew
            r("第一列")  = dr("第一列")
            r("第二列") = dr("第二列")
            r("第三列") = dr(nm)
        End If
    Next
Next

hhbb说得对，你的例子也太随便了。