Oracle log fn

Question

Hi All,
I was trying to convert the sybase log function to oracle, was able to complie the below code. However the results are not mathcing, could any one plz help me in correcting this
log error
example from my code is as below( I am using oracle 11g db) on sqldeveloper and toad.
Sybase = ytd_alpha = ((power(convert(float,10), sum(log10(w_acct/100+1)))-1)*100
-(power(convert(float,10),sum(log10(w_bogie/100+1)))-1)*100)*100
Oracle =((power(cast(10 as number),sum(log(10,w_acct/100+1)))-1)*100
-(power(cast(10 as number),sum(log(10,w_bogie/100+1)))-1)*100)*100     
--Oracle results
select ((power(cast(10 as number),sum(log(10,753/100+1)))-1)*100
-(power(cast(10 as number),sum(log(10,508/100+1)))-1)*100)*100 from dual;
=24500
--Sybase results
select ((power(convert(float,10), sum(log10(753/100+1)))-1)*100
-(power(convert(float,10),sum(log10(508/100+1)))-1)*100)*100
=20000I need to get the sybase result 20000, using oracle matching available functions.
plz dont get confuse with the lengthy calculation, I just c/p from my env.
I suspect it is log function causing the difference as Power is directly availabe in both syb & ora.
Edited by: NeilCSE on Sep 21, 2011 12:37 PM
Edited by: NeilCSE on Sep 21, 2011 12:42 PM

Answer 1

Without wading too deeply through it, I beleive Oracle is correct, and Sybase is converting to int for at least some of the operations.
In Sybase:
1> select log10(753/100+1)
2> /
             0.903090
(1 row affected)In Oracle
SQL> select log(10,753/100+1) from dual;
LOG(10,753/100+1)
       .930949031Back to Sybase with an explicit cast to float:
1> select log10(convert(float, 753)/100+1)
2> /
             0.930949
(1 row affected)The int return from the log10 impacts the rest of the calculations. Taking it a step further, and stripping out the uneccessary sum in both, and the cast to number in the Oracle version:
Sybase as posted
1> select power(convert(float,10), sum(log10(753/100+1)))-1
2> /
             7.000000
(1 row affected)Oracle:
SQL> select power(10,log(10,753/100+1))-1
  2  from dual;
POWER(10,LOG(10,753/100+1))-1
                         7.53Sybase again with cast to float:
1> select power(convert(float,10), sum(log10(convert(float,753)/100+1)))-1
2> /
             7.530000As a side note, the Sybase and Oracle databases are on different LPARs of a single physical server, so no funny stuff with different O/S or CPU designs :-)
John