From: Perrin Harkins
Date: February 24 2010 5:08pm
Subject: Re: EXPLAIN says DEPENDENT SUBQUERY despite no free variables
List-Archive: http://lists.mysql.com/mysql/220794
Message-Id: <66887a3d1002240908s678fa4a7gac570ffe50d5511@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1

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