As I know, IN sometimes invoke unmormal index.
On Thu, May 28, 2009 at 1:15 AM, Baron Schwartz <baron@stripped> wrote:
> On Wed, May 27, 2009 at 11:23 AM, Simon J Mudd <sjmudd@stripped> wrote:
> > perrin@stripped (Perrin Harkins) writes:
> >> On Wed, May 27, 2009 at 6:43 AM, Simon J Mudd <sjmudd@stripped>
> >> > So is the format of the DELETE FROM .. WHERE ... IN ( ... ) clause I
> >> > propose valid and SHOULD the optimiser recognise this and be expected
> >> > to just find the 2 rows by searching on the primary key?
> >> Not according to the docs:
> > I'm not sure that the reference makes anything clear. The statements
> > are wrote ARE valid SQL and even though containing mulitiple column
> > values ARE "constants".
> > Problem is I'm finding it hard to find a definitive reference to
> > like this. I'll have to check my Joe Celko books to see if he mentions
> Nothing's wrong with the SQL -- it's just that MySQL doesn't optimize
> this type of query well.
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