Re: Simple Query?

Koen Bok escreveu:
> I am doing some optimization on our search, but I need some advise...
>
> table: item
>
> id name
> --------------------------------------
> 1 iPod
> 2 Zune
> 3 Walkman
>
> table: search_item
>
> id_search id_item
> --------------------------------------
> 1 1
> 1 2
> 1 3
> 2 2
> 2 3
> 3 1
> 3 3
>
>
> Now what I want to have is the items that match with id_search 1 and 2
> and 3. Therefore I use the following SQL query.
>
> SELECT * FROM item WHERE id IN
> (SELECT id_item FROM search_item WHERE id_search=1 AND id_item IN
> (SELECT id_item FROM search_item WHERE id_search=2 AND id_item IN
> (SELECT id_item FROM search_item WHERE id_search=3)));
>
> This should only return id_item 3. Would this be the best SQL query to
> get this result? I have the feeling there should be something better,
> but I cannot find it. Anyone has a hint?
>

SELECT * FROM item WHERE id IN
(SELECT id_item FROM search_item WHERE id_search=1
INTERSECT
SELECT id_item FROM search_item WHERE id_search=2
INTERSECT
SELECT id_item FROM search_item WHERE id_search=3);

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