21 Aug 2008 10:00

Are you an SQL King?

I once met a person that used to write SQL queries more sophisticated than this:

select *
    from category
    where category_id IN
        (select cat1 as category_id
            from (select min(category_id) as cat1, max(category_id) as cat2, name, site_id, count(*)
                from category
                group by name, site_id
                having count(*) > 1
            ) as c1
        union    select cat2 as category_id
            from (select min(category_id) as cat1, max(category_id) as cat2, name, site_id, count(*)
                from category
                group by name, site_id
                having count(*) > 1
            ) as c2
        );

This one is to check duplicated categories in sites from Wikidot. It's not optimal, but it works. Of course the situation when there exist duplicated categories is a bug, but it seems a really rare one, because from the beginning of Wikidot, there are only 20 such categories, all of them being forum, so this probably means a small bug in create a forum thing as well.

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FIXED

Gabrys 21 Aug 2008 12:28

This bug is now fixed, folks :).

---

Piotr Gabryjeluk
visit my blog

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Unfold FIXED by Gabrys, 21 Aug 2008 12:28

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Blog Author

My name is Piotr Gabryjeluk.

I used to work for Wikidot Inc. as a web architect, developer and designer.
Now I work for Allegro Group as web programmer.

I have my own About page here.