Oracle Corporation supplies many built-in functions and packages. The following sections describe those used most often by PL/SQL developers.
The Oracle database provides dozens of built-in functions. Although most of these functions are available to both SQL and PLSQL, there are some notable exceptions. The DECODE function, for example, is not available to PL/SQL except within SQL statements included in your PL/SQL programs. The Oracle Database SQL Reference contains implementation details for the many functions defined to PL/SQL with the package STANDARD. You can view this package specification within the file stdspec.sql located in the ORACLE_HOME/rdbms/admin directory on the database server.
Converts string in any character set to the ASCII version of string in the database character set.
CAST(expression AS datatype)
Converts expression to type datatype. (Use as a powerful substitute for TO_DATE.)
Converts string to a ROWID datatype.
CONVERT(string, destination_character_set, source_character_set)
Converts string from the source character set to the destination character set. (The default source character set is the database character set.)
Adds time zone information to a TIMESTAMP value (converting it to a TIMESTAMP WITH TIME ZONE value).
Converts string containing hexadecimal characters to its raw equivalent. ...