Need to get previous but one record from PO in ax 2009

[pawan]

Dear kashperuk,
thanks for responding for my issue.
I will explain you the requirenment clearly below...
If we create "D1" PO with a +ve amount with a inventsiteid"123"
we should create "P1" with a -ve amount with same inventsiteid"123"




purchtable
Purchid enum(Drop/pick) timing for example inventsiteid
drop1 D day before yesterday 123
drop2 D yesterday 123
Pick1 P todays date n time 123

In my Cutomized Table:

N_Pick N_Drop inventsiteid
P1 D1 123

my req is to get D1 PO in the field of N_drop against P1 PO in the field N_pick

Please ask me if u need more info regarding this req...Hope you understand the issue..
Thanku