Loop through all fields and compare records

Hi,

Can anyone teach me how to loop in all fields? I have a table with a Emplid (not unique). The table store the history changes. what i want is when the field of the current record is empty. The empty field will be fill by the previous record. And those field of the current record that is not empty, will not be overwritten by the previous record.

Illustration:

Tprev: F1 F2 F3 F4 F5....

Tcurrent: _ f2 _  _   f5...

Tcurrent display =  F1 f2 F3 F4 f5

This Tprev and Tcurrent is the same Emplid and differ only in RecordSequence#. 

i already get their record position to determine which is the prev and the current record.

thanks,