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From:Dan Nelson Date:November 11 2002 4:08pm
Subject:Re: MySql 4.1 Sub Selects and not stored procedures
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In the last episode (Nov 11), Greg Matthews said:
> 
> hey, can i hijack my message back?...this thread is about the performance of
> subselects, not stored procedures. go write your own message :-)...
> 
> so....the original question is if someone would be nice enough to answer..
> 
> ====> Do any MySql coders writing subselects in 4.1 know whether EXISTS will
> outperform an equivalent query written as a join. <=====
> 
> Typically, db vendors recommend you use an exists clause, not a join
> when testing for the presence of child data because it's faster.

I would expect that the explain plans for both queries would end up
being identical, so the only difference is whichever you think is more
readable.

I don't remember reading any Oracle documentation recommending
subselects.

-- 
	Dan Nelson
	dnelson@stripped
Thread
MySql 4.1 Sub SelectsGreg Matthews10 Nov
  • Re: MySql 4.1 Sub SelectsJeremy Zawodny10 Nov
  • Re: MySql 4.1 Sub SelectsGreg Matthews10 Nov
    • Re: MySql 4.1 Sub SelectsJeremy Zawodny10 Nov
  • Re: MySql 4.1 Sub SelectsJocelyn Fournier10 Nov
  • Re: MySql 4.1 Sub SelectsGreg Matthews10 Nov
    • Re: MySql 4.1 Sub SelectsJeremy Zawodny10 Nov
  • Re: MySql 4.1 Sub SelectsHarald Fuchs10 Nov
  • Re: MySql 4.1 Sub SelectsGreg Matthews10 Nov
  • Re: MySql 4.1 Sub SelectsMichael T. Babcock11 Nov
  • Re: MySql 4.1 Sub SelectsGreg Matthews11 Nov
RE: MySql 4.1 Sub Selectsdaniel11 Nov
  • re: RE: MySql 4.1 Sub SelectsVictoria Reznichenko11 Nov
    • RE: RE: MySql 4.1 Sub SelectsDan Rossi11 Nov
      • Re: RE: MySql 4.1 Sub Selects and not stored proceduresGreg Matthews11 Nov
        • RE: RE: MySql 4.1 Sub Selects and not stored proceduresArthur Fuller11 Nov
          • Re: RE: MySql 4.1 Sub Selects and not stored proceduresGreg Matthews11 Nov
        • Re: MySql 4.1 Sub Selects and not stored proceduresDan Nelson11 Nov
        • Re: RE: MySql 4.1 Sub Selects and not stored proceduresJohn Ragan11 Nov
      • Re: MySql 4.1 Sub SelectsMichael T. Babcock11 Nov
re[2]: MySql 4.1 Sub SelectsRichard Morton11 Nov
  • Re: re[2]: MySql 4.1 Sub SelectsLenz Grimmer11 Nov