SELECT
ASCII('A'),
CHR(65),
LPAD('STRING', 10, '-' ),
RPAD('STRING', 10),
LTRIM('STRING','AN'),
RTRIMG('STRING'),
INSTR('STRING1', 'STRING2', 1), //first
INSTRB('STRING1', 'STRING2', POSITION),
SUBSTRING('STRING1', POSITION, LENGTH),
SUBSTRING('STRING1', POSITION, LENGTH IN BYTE),
LENGTH('STRING'),
TO_CHAR('VALUE','FORMAT'),
TO_NUMBER('STRING','STRING'S FORMAT),
TO_DATE('STRING','STRING'S FORMAT),
ROUND(NUMBER, POSITION),
CEIL(NUMBER),
TRUNC(NUMBER, POSITION)

FROM DUAL;