Christopher Kings-Lynne <chriskl@familyhealth.com.au> wrote:
>> Mysql is planning on making this work:
>>
>> SELECT id, @a:=COUNT(*), SUM(sum_col)/@a FROM table_name GROUP BY
>> id.
>>
>> Do we have anything like it (After a discussion with Tom i figure
>> no). User variables is nice, especially in these kind of queries.
>
> Well of course they have to make that work - they don't have
> subselects :P
>
> Chris
Yeah, but there is a point about running count(*) one time too many.
Say if i would like to get a prettyprinting query like this:
SELECT id, @a:=COUNT(*), sum_col::text||'/'@a::text FROM table_name;
That would be DAMN expensive doing with a subselect:
SELECT id, sum_col||'/'||(select COUNT(*) from tabe_name) FROM
table_name;
I know this example suck eggs, but you get the point where it hurts,
right?
Magnus - sorry for the dupe, chris