oracle form problem

hi,

i’ve form in tabular format. my problem is on the basamt text item if on the next row
the iexcod is ROOM the value of BASAMT ( 300 ) on previous record which is the iexcod is ROOM.
the 300 will be deducted to a variable basic_amount equals to 500 therefore on the third row
the basamt equals to 200…

basamt is a calculated field.

layout :

IEXCOD EXPCODE DAYS ACTEXP BASAMT

ROOM NURSE 1 50000 300
MISC MISCD 1 50000 400
ROOM SURG 1 50000 200 <<<--- 3rd row desired output thanks, danny