2011/05/14 21:47 +0200, misiaq
You're right about explain. That is why I suggested to use explain EXTENDED and
then SHOW WARNINGS.
Second query will show you the optimizer output. As far as I understand - that
was the par of your question.
Yes, I did that. That output showed no
2011/05/14 21:47 +0200, misiaq
You're right about explain. That is why I suggested to use explain EXTENDED and
then SHOW WARNINGS.
Second query will show you the optimizer output. As far as I understand - that
was the par of your question.
Yes, I did that.
--
MySQL General M
h...@tbbs.net wrote:
> 2011/05/12 15:15 +0200, misiaq
> h...@tbbs.net wrote:
> (...)
> >
> > Is the optimizer so clever as to set that test outside the expression, and
> > only then evaluate it when "houmuch" and "SharePrice" are not equal?
> >
> >
>
> Try it yourself:
> mysql > ex
2011/05/12 15:15 +0200, misiaq
h...@tbbs.net wrote:
(...)
>
> Is the optimizer so clever as to set that test outside the expression, and
> only then evaluate it when "houmuch" and "SharePrice" are not equal?
>
>
Try it yourself:
mysql > explain extended select * from table1;
and the
h...@tbbs.net wrote:
(...)
>
> Is the optimizer so clever as to set that test outside the expression, and
> only then evaluate it when "houmuch" and "SharePrice" are not equal?
>
>
Try it yourself:
mysql > explain extended select * from table1;
and then
mysql > show warnings;
You will see
ADDDATE(ereStart, (SELECT hwyl FROM Stock) * NULLIF(Houmuch, (SELECT SharePrice
FROM Stock)) / (SELECT regularPayment FROM Stock)) AS goodThrough
Buried in the middle of the foregoing expression is a NULLIF, because of which
the whole thing is NULL if "houmuch" and "SharePrice" are equal. Thus t
