comparing current row with previos and next row in a table

you must define identity column or there should be an integer column to keep the sequence of the rows, or you can import the data into a temporary table with an additional identity column.

here is the script:

Create Table #Temp
(I_Col int identity(1,1)
,val1 int
)

Insert into #Temp values(10)
Insert into #Temp values(25)
Insert into #Temp values(67)
Insert into #Temp values(98)
Insert into #Temp values(11)

Select * From #Temp

I_Col (identity column)	Val1
1	10
2	25
3	67
4	98
5	11

Select Curr.val1 Current_Value
,isnull(Prev.val1,0) Prev_Value
, isnull(_Next.val1,0) Next_Value
From #Temp Curr
Left outer Join #Temp Prev On Prev.I_Col = Curr.I_Col -1
Left Outer Join #Temp _Next On _Next.I_Col = Curr.I_Col + 1

Current_Value	Prev_Value	Next_Value
10	0	25
25	10	67
67	25	98
98	67	11
11	98	0