Some useful functions from Oracle database 11g

Replace(char, str1, str2) Replaces every occurrence of str1 in char with str2.

Length(char) Returns the length of the char.

Initcap(char) Changes the first character of each element in char to uppercase.

Power(m,n) Multiplies m to the power n.

Sqrt(n) Returns the square root of n.

Current_timestamp Returns the current timestamp along with the time zone offset.

YEAR year spelled out. For example: select to_char(sysdate, 'YEAR') from dual;------- TWENTY ELEVEN

WW week of year. For example: select to_char(sysdate, 'WW') from dual;

W week of the month. For example: select to_char(sysdate, 'W') from dual;

DDD Day of the year. For example: select to_char(sysdate, 'DDD') from dual;

DD Day of the month. For example: select to_char(sysdate, 'DD') from dual;

D Day of the week. For example: select to_char(sysdate, 'D') from dual;

These are all from "Oracle Database 11g, A Beginner's Guide"