Getting a value from a field if you only know the field ID

static void Job4(Args _args)
{
    CustTable   custTable;
    FieldId     fieldId;
    ;
 
    fieldId = fieldNum(CustTable, AccountNum); // This could be passed as a method parameter
 
    select custTable; // Get first record
 
    print custTable.(fieldId); // Print account number
 
    select custTable
        where custTable.(fieldId) == '1101';  // Where clause based on field ID
 
    print custTable.Name;
    pause;
}