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From:Paul DuBois Date:August 11 1999 8:41pm
Subject:Re: Use (problem with?) LIMIT in select statement
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At 8:31 PM +0200 8/11/99, Christian Mack wrote:
>tonu-mysql@stripped wrote:
>>
>> On Wed, 11 Aug 1999, Paul McAvoy wrote:
>>
>> > Hi, I am currently using Mysql 3.22.25-1 (RPM).  I think that I 
>>may have found
>> > a bug, or it may be that I am unclear on how the select statement works.
>> >
>> > My Query is similar to this:
>> >
>> > SELECT id,name FROM list ORDER BY name LIMIT 20;
>> >
>> > I was under the impression that teh LIMIT clause was used to limit the
>> > return set.
>>
>>   Yes, it must work like you understood. It must order all items in your
>> table and THEN take the first 20 records and give them back. If it does
>> something different, then it's wrong.
>>
>>     Tonu
>
>Hi
>
>Mysql doesn't do this.
>As described in the manual mysql will stop getting results, when it 
>reached the given amount.
>It will only satisfy the WHERE part of your query.
>The ordering is done after getting the results.
>So you get with the above SELECT 20 rows which are ordered, not the 
>first 20 from the ordered list.


?

Are you sure about that?  I thought that LIMIT was something like 
HAVING in that
it post-processes the result set after having determined what the result set
was.

If that's not so, then why does a LIMIT 20 query on a table with a zillion rows
take longer than on a table with a few rows?

-- 
Paul DuBois, paul@stripped
Thread
Use (problem with?) LIMIT in select statementPaul McAvoy11 Aug
  • Re: Use (problem with?) LIMIT in select statementtonu-mysql11 Aug
    • Re: Use (problem with?) LIMIT in select statementChristian Mack11 Aug
      • Re: Use (problem with?) LIMIT in select statementtonu-mysql11 Aug
        • Re: Use (problem with?) LIMIT in select statementSteve Edberg11 Aug
        • Re: Use (problem with?) LIMIT in select statementTonu Samuel11 Aug
      • Re: Use (problem with?) LIMIT in select statementSteve Ruby11 Aug
      • Re: Use (problem with?) LIMIT in select statementThimble Smith11 Aug
        • Re: Use (problem with?) LIMIT in select statementPaul McAvoy11 Aug
      • Re: Use (problem with?) LIMIT in select statementPaul McAvoy11 Aug
      • Re: Use (problem with?) LIMIT in select statementPaul DuBois11 Aug
    • Re: Use (problem with?) LIMIT in select statementChristian Mack12 Aug
RE: Use (problem with?) LIMIT in select statementClinton11 Aug