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From:Csongor Fagyal Date:December 11 2002 7:43pm
Subject:Re: Select Where !=
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Michelle de Beer wrote:

>I have two tables. One with names and one for
>excluding certain names. Exclude-table contains the
>uid for the name excluded.
>
>If I want to see which names has been excluded, this
>query does the job:
>Select n.uid, n.name from names_tables n, exclude
>WHERE n.uid = exclude.n_uid 
>
>But if I want to select all names, but leave out the
>ones that are in the "exclude"-table, I thought this
>would do it, but no.
>Select n.uid, n.name from names_tables n, exclude
>WHERE n.uid != exclude.n_uid 
>
>It has something to do with the != thingy...
>
>Any thoughts?
>  
>
You are trying to do a join in a way you should not :-) Generally it is 
a bad idea to do a join based on a non-equality. It does not do what you 
think it does. (Look into how relational databases and joins work.)

You should select your excluded values from the exclude table, the 
subtract irrelevant rows from table n. Are you using MySQL 3.xxx or 4.xxx?

- Cs.




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Re: Select Where !=Csongor Fagyal11 Dec