Help With Time Series Fluctuation???

Hi All,
I have a table Test1:
ID date Value
AAUGVAL 2/27/198760.848
AAUGVAL 3/2/1987 64.288
AAUGVAL 3/3/1987 63.77
AAUGVAL 3/4/1987 62.495
AAUGVAL 3/5/1987 62.65
AAUGVAL 3/6/1987 62.548
AAUGVAL 3/9/1987 62.292
AAUGVAL 3/10/198763.045
AAUGVAL 3/11/198763.021
....
I am trying to see the value % changes day by day and here is is the code I wrote:
select
starttime=cast(v.date as char(8)), endtime=cast(a.date as char(8)),
startval=v.Value, endval=a.Value,
change=substring('- +', sign((a.Value-v.Value)+2,1)+ cast(abs(a.Value-v.Value) as varchar)
from
(select date,Value, ranking =(select count(distinct date) from Test1 T where T.Value<=S.Value)
from Test1 S) v left outer join
(select date,Value, ranking=(select count(distinct date) from Test1 T where T.Value<=S.Value)
from Test1 S) a
on( a.ranking=v.ranking+1)

I got the following error message:
Server: Msg 174, Level 15, State 1, Line 4
The sign function requires 1 arguments.
Server: Msg 170, Level 15, State 1, Line 7
Line 7: Incorrect syntax near 'v'.
Server: Msg 170, Level 15, State 1, Line 9
Line 9: Incorrect syntax near 'a'.

Could someone please help with this? Thank you in advance!
shiparsons