For Each dr As Row In Tables("表A").Rows
If dr("字段2") = dr("字段3") Then
Dim flag = True
For Each ddr As DataRow In DataTables("表B").SQLSelect("字段1='" & dr("字段1") & "'")
If ddr("字段2") <> ddr("字段3") Then
flag = False
Exit For
End If
Next
If flag = True Then
dr("字段5") =1
End If
End If
Next