Precision of the POWER function

Question

Hi,
I found something strange with the POWER function.
In SQLPLUS (or SQL Developer)
SQL> column test format 9.9999999999999999999999999999999999999999999
SQL> select power(9,0.5) test from dual;
TEST
3.0000000000000000000000000000000000000100000
SQL> select power(4,0.5) test from dual;
TEST
1.9999999999999999999999999999999999999900000
These results should be equal respectively to 3 and 2? SQRT function returns the correct result... Is it a bug or did I miss something in my maths course?? ;o)
Thanks
Christophe

Answer 1

You will get that ->
satyaki>
satyaki>select * from v$version;
BANNER
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - Prod
PL/SQL Release 10.2.0.3.0 - Production
CORE    10.2.0.3.0      Production
TNS for 32-bit Windows: Version 10.2.0.3.0 - Production
NLSRTL Version 10.2.0.3.0 - Production
Elapsed: 00:00:00.26
satyaki>
satyaki>select round(power(9,0.5)) test from dual;
      TEST
         3
Elapsed: 00:00:01.00
satyaki>
satyaki>select round(power(4,0.5)) test from dual;
      TEST
         2
Elapsed: 00:00:00.04
satyaki>
satyaki>Regards.
Satyaki De