Re: [SQL] optimize self-join query

[Ty Busby]

Thanks to everyone for all the thoughtful responses.  They have been incredibly 
helpful.

Ended up optimizing per Lee, and creating buckets per Tom.  Thanks again.

On Oct 25, 2011, at 2:37 PM, Ty Busby wrote:

I have a table that stores a very large starting number called 
epc_start_numeric and a quantity.  I've apparently built the most inefficient 
query possible for doing the job I need: find out if any records overlap.  
Imagine the epc_start_numeric + quantity representing a block of numbers.  I 
need to find out if any of these blocks overlap.


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Re: [SQL] Different order by behaviour depending on where clause?

[Jan Bakuwel]

Hi Phil,

Thanks for your reply.


On 28/10/11 23:25, Phil Couling wrote:
> Hi Jan
>
> It is my understanding that a select query without "order by" has an
> undefined order.
> Though I'm sure you understand the dangers of using something which is
> undefined, I'm going reiterate them here:

I think you might have misread my email, I'm quoting:

"I have a compound query with some grouping, having and order by's saved
as a view, say with name "myview".

So... I am using explicit order by's. The problem (now solved) was that
I somewhere subtle "hidden" in one of my subqueries, type casted a row
(varchar to int) but omitted to do the same one or two "levels up". This
messed up my sorting. Once I applied the type cast in every single bit
of statement or all (sub)selects, all was OK.

kind regards,
Jan


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