Re: [Q] Daves's top 10 SQL question

youngpa_at_statcan.ca (Paul Young) wrote:

>But seriously, how can you code a SQL query to first order records
>greatest to least then pick out only a pre-selected number of them
>without prior knowledge of their distribution. This strikes me as
>a common, even simple thing to do, but I can't see how to do it, and
>I've written some pretty twisted queries.

Unfortunately, Oracle 7 doesn't have a LIMIT TO clause such as Rdb has. The closest match is WHERE ROWNUM <= 10. But this is not at all reliable because the ROWNUM clause may be evaluated and parsed during the select phase, before the rows are sorted. Sorry.

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| Chris Fischer                           cfischer_at_nando.net |
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