How to compare NUMBER's

Table t1 has two fields s1,s2 both with type NUMBER(9,3),

After I exectue following sql,
"SELECT s1, (s1-s2)/s2 FROM t1"

result is:
000001, .872
000002, 0

While executing "SELECT s1, (s1-s2)/s2 FROM t1 WHERE (s1-s2)/s2>0.5",

result is:
no rows effected.

Why not "000001, .872"?

I wonder what's wrong if I write the condition in WHERE clause as
"(s1-s2)/s2>0.5"?

Thanks in advance. Received on Wed Aug 08 2007 - 00:19:59 CDT