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Oracle Tutorials - What Is NULL in PL/SQL
(Continued from previous topic...)
What Is NULL in PL/SQL?
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:
next_task := NULL; -- NULL value
IF next_task IS NOT NULL THEN
DBMS_OUTPUT.PUT_LINE('I am busy.');
DBMS_OUTPUT.PUT_LINE('I am free.');
IF next_task IS NULL THEN
NULL; -- NULL statement
DBMS_OUTPUT.PUT_LINE('... working on ' || next_task);
This script should print this:
I am free.
(Continued on next topic...)
- Is PL/SQL Language Case Sensitive?
- How To Enter Comments in PL/SQL?
- What Are the Types of PL/SQL Code Blocks?
- What Is an Anonymous Block?
- What Is a Named Program Unit?
- What Is a Procedure?
- What Is a Function?
- How To Declare a Local Variable?
- How To Initialize Variables with Default Values?
- How To Assign Values to Variables?
- What Are the Arithmetic Operations?
- What Are the Numeric Comparison Operations?
- What Are the Logical Operations?
- How Many Categories of Data Types?
- How Many Scalar Data Types Are Supported in PL/SQL?
- How To Convert Character Types to Numeric Types?
- What Are the Execution Control Statements?
- How To Use "IF" Statements on Multiple Conditions?
- How To Use "WHILE" Loop Statements?
- How To Use "FOR" Loop Statements?
- What Is NULL in PL/SQL?
- How To Test NULL Values?