Prevous value based different Column

[pandiarajan]

Dear all,

     i want to reduce stock value based on previous location and Item

Find Below My Input Data :

Location	Item	LineID	Days	Req	Available
XXX	ABC	Line1	46	1	32
XXX	ABC	Line2	40	1	32
YYY	ABC	Line3	55	1	6
YYY	ABC	Line4	43	1	6
YYY	ABC	Line5	40	1	6
YYY	ABC	Line6	34	1	6
YYY	ABC	Line7	23	1	6
YYY	ABC	Line8	5	1	6
YYY	ABC	Line9	3	1	6

I want this Output

Location	Item	LineID	Days	Req	Available	output
XXX	ABC	Line1	46	1	32	31
XXX	ABC	Line2	40	1	32	30
YYY	ABC	Line3	55	1	6	5
YYY	ABC	Line4	43	1	6	4
YYY	ABC	Line5	40	1	6	3
YYY	ABC	Line6	34	1	6	2
YYY	ABC	Line7	23	1	6	1
YYY	ABC	Line8	5	1	6	0
YYY	ABC	Line9	3	1	6	-1