List:General Discussion« Previous MessageNext Message »
From:Perrin Harkins Date:February 24 2010 5:08pm
Subject:Re: EXPLAIN says DEPENDENT SUBQUERY despite no free variables
View as plain text  
On Wed, Feb 24, 2010 at 10:11 AM, Yang Zhang <yanghatespam@stripped> wrote:
> Any ideas on
> how to optimize this by convincing mysql to see the independence use a
> const join?

http://www.xaprb.com/blog/2006/04/30/how-to-optimize-subqueries-and-joins-in-mysql/

You need to rewrite as a join or use a FROM subquery.  You should
pretty much always avoid using IN/NOT IN.

- Perrin
Thread
EXPLAIN says DEPENDENT SUBQUERY despite no free variablesYang Zhang24 Feb
  • Re: EXPLAIN says DEPENDENT SUBQUERY despite no free variablesPerrin Harkins24 Feb
    • Re: EXPLAIN says DEPENDENT SUBQUERY despite no free variablesDan Nelson25 Feb
      • Re: EXPLAIN says DEPENDENT SUBQUERY despite no free variablesJohan De Meersman25 Feb
      • Re: EXPLAIN says DEPENDENT SUBQUERY despite no free variablesPerrin Harkins25 Feb
  • Re: EXPLAIN says DEPENDENT SUBQUERY despite no free variablesBaron Schwartz25 Feb