What Is NULL Value in Oracle

Q

What Is NULL Value in Oracle?

✍: FYIcenter.com

A

NULL is a special value representing "no value" in all data types. NULL can be used on in operations like other values. But most operations has special rules when NULL is involved. The tutorial exercise below shows you some examples:

SET NULL 'NULL'; -- Make sure NULL is displayed

SELECT NULL FROM DUAL;
N
-
N
U
L
L

SELECT NULL + NULL FROM DUAL;
 NULL+NULL
----------
NULL
  
SELECT NULL + 7 FROM DUAL;
    NULL+7
----------
NULL

SELECT NULL * 7 FROM DUAL;
    NULL*7
----------
NULL


SELECT NULL || 'A' FROM DUAL;
N
-
A

SELECT NULL + SYSDATE FROM DUAL;
NULL+SYSD
---------
NULL

 

Understanding SQL Language Basics for Oracle

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2016-10-16, 135👍, 0💬