主题：筛选每月第一天时空表有一行代码如何写

Dim y As Integer = 2011 '指定年份
Dim m As Integer = 6 '指定月份
Dim dt1 As New Date(y, m, 1)
Dim dt2 As New Date(y, m, Date.DaysInMonth(2011,6)) '获取该月的最后一天
Dim Filter As String
Filter = "日期 >= #" & dt1 & "# And 日期 <= #" & dt2 & "#"
if DataTables("订单").find(Filter) Is Nothing Then ‘如果这个月没有数据
     Dim dr As DataRow  = DataTables("订单").AddNew()
     dr("日期") = dt1
End if