strange behaviour - Mailing list pgsql-general

From Mathieu Arnold
Subject strange behaviour
Date
Msg-id 5.0.2.1.2.20010225133146.00a08080@wheresmymailserver.com
Whole thread Raw
Responses Re: strange behaviour  (Peter Eisentraut <peter_e@gmx.net>)
List pgsql-general
Hi

could someone explain this to me :

sympa=> select count(*) from subscriber_table;
  count
-------
  14029
sympa=> select count(*) from subscriber_table where bounce_subscriber =
NULL;
  count
-------
  14024
sympa=> select count(*) from subscriber_table where bounce_subscriber <> NULL;
  count
-------
      0
sympa=> select count(*) from subscriber_table where bounce_subscriber = '';
  count
-------
      0
sympa=> select count(*) from subscriber_table where bounce_subscriber <> '';
  count
-------
      5

I was thinking that "= NULL" and "<> NULL" were oposite and that "<> NULL"
would give me the result i had with "<> ''" or am I mistaken ?

--
Mathieu Arnold


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