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> wrote:
>> > 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 something
> like this. I'll have to check my Joe Celko books to see if he mentions ths.
Nothing's wrong with the SQL -- it's just that MySQL doesn't optimize
this type of query well.