Copy one field value in to another field in same table in Ax

1-Create Table --->TableA

2-Add Two fields Num and SerialNumberFormat

3-Run following job after inserting data in Num Field

static void OneFieldToAnotherField(Args _args)
{
    TableA  t1;
    ;
    ttsbegin;
    while select forupdate t1 where t1.Num == t1.num
    {
         t1.SerialNumberFormat = t1.num;
         t1.Num = "";
         t1.update();
    }
    ttscommit;
}

==============================================
code for update data for all company in ax:

static void JobTest(Args _args)
{
    DataArea  DataArea;
    TableA  t1;

   while select DataArea where !DataArea.isVirtual
    {
        t1.clear();
        t1 = null;
        changecompany (DataArea.Id)
        {
         ttsbegin;
   
    while select forupdate    t1 where t1.Num == t1.num
                                       && t1.dataAreaId == t1.dataAreaId
    {
         t1.SerialNumberFormat = t1.num;
         //t1.Num = "";
         t1.doUpdate();
    }
    ttscommit;
        t1= null;
    }
     
        }
    }