Giovanna Pavarani <[EMAIL PROTECTED]> wrote:
> i'm sorry if this kind of question was already posted, i'm a newbie and
> i hope you will find anyway the time to answer me.
>
> I've installed mysql version 4.0.12-nt on my Windows XP Professional
> notebook and mysql version 4.0.12-standard on a Solaris 8 machine.
>
> Some antefacts:
> I need a very very small database to keep track of a set of discussion
> topics, a set of users and the subscriptions of the users to the
> discussion topics.
>
> This is my database (a poor designed one, i know):
>
[skip]
>
> what i'd need is to present the user a list of the topics that he's not
> yet subscribed.
> I read the MySQL manual and I found that NOT IN and the nested SELECTs
> are not supported in this version, so I ended up to use temporary tables.
>
> These are the queries that i use:
>
> CREATE TEMPORARY TABLE user03 (TopicName varchar(40));
> INSERT INTO user03 SELECT TopicName FROM subscriptions WHERE
> SipUri='[EMAIL PROTECTED]';
> SELECT topics.TopicName FROM topics,user03 WHERE topics.TopicName !=
> user03.TopicName;
It's not correct query, because it gives you cartesian product of not equal TopicName.
As to query with NOT IN you can rewrite it with LEFT JOIN as described at:
http://www.mysql.com/doc/en/ANSI_diff_Sub-selects.html
>
> They are working fine on XP, the result is the list of topics at which
> user03 isn't subscribed yet. But on Solaris, with the same database, the
> result is a list of all the topics, repeated a certain number of times.
>
>
> I'm stucked on this, is it possible that the problem is the
> 4.0.12-standard version? Should I use the 4.0.12-max version? Or am i
> missing something?
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