RE: comparing null values

From: Mercadante, Thomas F <NDATFM_at_labor.state.ny.us>
Date: Thu, 30 Jan 2003 11:20:11 -0800
Message-ID: <F001.0053F5CA.20030130112011@fatcity.com>

Fred,

because a null value is not "not like" anything in the world. by definition, a null is not comparable to anything. it is null. you cannot check to see if something is comparable to null.

you can, however, change your query to say:

SQL> select * from tester2 where nvl(whatever,'<null>') not like '%STU%';

and it will work just fine.

Tom Mercadante
Oracle Certified Professional

-----Original Message-----
Sent: Thursday, January 30, 2003 12:42 PM To: Multiple recipients of list ORACLE-L

Can anyone explain why it is that I seem unable to use 'like' and 'not like'

on columns containing null values. (I am unable to find information regarding this on MetaLink.)

For example:

SQL> select * from tester2;

COL1 COL2 WHATEVER
---- ---- --------
1 1 STUFF
2 2 STUFF
3 3
4 4

SQL> select * from tester2 where whatever not like '%STU%'; no rows selected

My question is why does this not return the 3 & 4 columns?

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Author: Gary Jackson
  INET: fred_fred_1_at_hotmail.com

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Author: Mercadante, Thomas F
  INET: NDATFM_at_labor.state.ny.us

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To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). Received on Thu Jan 30 2003 - 13:20:11 CST