主题：[求助]根据一条记录而判断对应添加n条记录

其实很简单：

Dim nms1() As String = {"日期","内容","次数","时间"}
Dim nms2() As String = {"前座_左","前座_右","后座_左","后座_右"}
DataTables("表B").DataRows.Clear()
For Each dr1 As DataRow In DataTables("表A").DataRows
   For Each nm2 As String  In nms2
        If  dr1.IsNull(nm2 & "_姓名") = False
            Dim dr2 As DataRow = DataTables("表B").AddNew
            dr2("姓名") = dr1(nm2 & "_姓名")
            dr2("类型") = dr1(nm2 & "_科目")
            For Each nm1 As String In nms1
                dr2(nm1) = dr1(nm1)
            Next
        End If
    Next
Next

1、不管几个表，道理是一样的。

2、不能用表达式实现。

既然思路很清楚，你就自己写一下吧，至少应该去尝试一下。