SQL & PL/SQL

Hello,

The instruction EXTRACT have an error:

SELECT SYSDATE, EXTRACT(YEAR FROM SYSDATE) "AÑO",
EXTRACT(MONTH FROM SYSDATE) MES,
EXTRACT(DAY FROM SYSDATE) DIA,
EXTRACT(MINUTE FROM systimestamp) MINUTOS,
EXTRACT(SECOND FROM systimestamp) SEGUNDOS
FROM DUAL;

when you execute the instruction it is succefull, but if you add the next:
SELECT EXTRACT(HOUR FROM systimestamp) HORA FROM DUAL;

you can check that the hour is not correct, but with te traditional to_char : SELECT to_char(systimestamp,'hh24') from dual;
Is succefull.

Thanks for your atention.