Re: Q on views and performance

On 2008-02-23 08:49, Dean Gibson (DB Administrator) wrote:
> Why 10,000 views??? What's wrong with the ONE view above? You DON'T
> want to be defining VIEWs based on actual tables VALUES; leave that
> to the SELECT. For that matter, what's wrong with the final SELECT I
> listed (below)?
>
> SELECT a1.word AS word1, a2.word AS word2
> FROM S JOIN T a1 USING( word )
> LEFT JOIN T a2 USING( zipk )
> WHERE a1.type = <int1> AND a2.type = <int2>;
>
> -- Dean
Amendment: I forgot, that if it's a LEFT JOIN you have to write it as:

SELECT a1.word AS word1, a2.word AS word2
FROM S JOIN T a1 USING( word )
LEFT JOIN T a2 USING( zipk )
WHERE a1.type = <int1> AND (a2.type = <int2> OR a2.type IS NULL);

-- Dean

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