Decode – compares expression to each search value one by one.
Instr – search string for substring.
Round – returns a number or date rounded.
Substr – returns a set of characters from an expression.
To_Char – converts an expression to a character set.
To_Date – converts a character set to a value of DATE data type.
To_Number – converts expression to a value of NUMBER data type.
Trim – trim leading or trailing characters from a character string.
Trunc – truncates an expression to a number or to a date.