Dim cmd As New SQLCommand
cmd.CommandText = "s elect [_Identify] from"
cmd.CommandText += "(s elect 户号, max(年龄) As 年龄 from {表A} group by 户号) as a"
cmd.CommandText += " inner join {表A} as b on a.户号 = b.户号 And a.年龄 = b.年龄"
Dim dt As DataTable = cmd.ExecuteReader()
DataTables("表A").DeleteFor("_Identify not in (" & dt.GetComboListString("_Identify").Replace("|",",") & ")")