InsertRecordSet Example in Ax 2012

void clicked()
{
    Usmf_CustomerTable  _CustomerTable;
    Usmf_CustDetails    _Usmf_CustDetails;
    date date1,date2;
    str cust;

    super();
    delete_from  Usmf_CustDetails;
    date1   = Fromdate.dateValue();
    date2   = Todate.dateValue();
    cust    = custGroup.valueStr();
    if(date1 != dateNull() && date2 != dateNull() && cust !="")
    {
       insert_recordset Usmf_CustDetails(UsmfID,TransDate,CustomerGroup,CustName)
                        select UsmfID,TransDate,CustomerGroup,CustName from _CustomerTable
                                  where _CustomerTable.TransDate >= date1
&&    _CustomerTable.TransDate <= date2
&&    _CustomerTable.CustomerGroup == custGroup.valueStr();
    }
    else if(date1 != dateNull() && date2 != dateNull())
    {
       insert_recordset Usmf_CustDetails (UsmfID,TransDate,CustomerGroup,CustName)
              select UsmfID,TransDate,CustomerGroup,CustName from _CustomerTable
                                where _CustomerTable.TransDate >= date1
&&      _CustomerTable.TransDate <= date2 ;

    }
    else if(date1 == dateNull() && date2 == dateNull() && cust != " ")
   {
        insert_recordset Usmf_CustDetails (UsmfID,TransDate,CustomerGroup,CustName)
                         select UsmfID,TransDate,CustomerGroup,CustName from _CustomerTable
                                where   _CustomerTable.CustomerGroup == custGroup.valueStr();
  }
  Usmf_CustDetails_ds.research();
}

//Second Example

//insert record set....

insert_recordset Usmf_CustDetails (UsmfID,TransDate,CustomerGroup,CustName)
                        select UsmfID,TransDate,CustomerGroup,CustName
                                from _CustomerTable
                                where   _CustomerTable.CustomerGroup == custGroup.valueStr();
//insert record set.....