Re: query issue

From: Ed Prochak <ed.prochak_at_magicinterface.com>
Date: Mon, 09 Feb 2004 01:05:20 -0500
Message-ID: <d2FVb.2911$ch2.2230@fe01.usenetserver.com>

curwen wrote:

>>To add to what Daniel said.. in a blunt way using nice friendly
>>letters... empty your cup of preconceptions of what you think a RDBMS
>>is and then fill it with some RTFM'ing.

>
>
> I know you'll probably start to rolling on the floor laughing,
> but I'm gonna ask anyway:
> what the h*** is a rtfm'ing ?

Read The F***ing Manual

You can fill in the blanks, I'm sure. 8^)
>
>
>

>>>I've tried the the following , but doesn't work:
>>>
>>>select distinct numb,fk1
>>>from <table>
>>
>>It does work - just not the way you think. :-) 

>
>
> hey, what's up ?
> I'm writing in a It Professional newsgroup
> I'm expecting to find people smart enough to understand even if I
> don't write it down entirely what I was trying to say.. ;)

As sybrand would tell you, all our crystal balls are broken.

>
> anyway, to explain myself better, the desidered behaviour is the one
> that comes out from the following:
>
> select n_id,n_number,fk1 FROM numbers
> where n_id in
> (select max(n_id) from numbers group by n_number)
>
> I'm just worried about performances:
> my question was :'is there any way to avoid nestes queries'?
>
> ps ..and getting the same result, of course
>
> regards
> jc

Let's see, this query is DIFFERENT from the one in your original post, so it's good we didn't try to answer based on that post, right?

How about either explaining your business problem in prose OR provide a small set of sample data to demonstrate your problem? We still have no clue why you would want to write a query like that.

Just some additional thoughts:

• DISTINCT is bad practice, IMHO.
• Rather than a subquery, why not use an in-line VIEW?
• First get the logic right. Only after testing proves there's a performance issue should you even think about optimization. (and, lucky you, at that point you can do a trace and find exactly WHRE the bottleneck is)
• There are no stupid questions.

-- 
Ed Prochak
running    http://www.faqs.org/faqs/running-faq/
netiquette http://www.psg.com/emily.html
--
"Two roads diverged in a wood and I
I took the one less travelled by
and that has made all the difference."
robert frost

Received on Mon Feb 09 2004 - 00:05:20 CST