What Is NULL in PL/SQL

Q

What Is NULL in PL/SQL? - Oracle DBA FAQ - Understanding PL/SQL Language Basics

✍: FYIcenter.com

A

NULL is a reserved key word and it stands for two things in PL/SQL:

  • NULL is an executable statement, and means doing nothing.
  • NULL is a data balue, and means no value.

The following sample script shows you examples of using NULL keyword:

DECLARE
  next_task CHAR(80);
BEGIN
  next_task := NULL; -- NULL value

  IF next_task IS NOT NULL THEN
     DBMS_OUTPUT.PUT_LINE('I am busy.');
  ELSE
     DBMS_OUTPUT.PUT_LINE('I am free.');
  END IF;
  
  IF next_task IS NULL THEN
     NULL; -- NULL statement
  ELSE
     DBMS_OUTPUT.PUT_LINE('... working on ' || next_task);
  END IF;
END;

This script should print this:

I am free.

2007-04-29, 4779👍, 0💬