Re: How to re-sort a sorted query? - Mailing list pgsql-sql

From Oliver Elphick
Subject Re: How to re-sort a sorted query?
Date
Msg-id 1098822881.2414.42.camel@linda
Whole thread Raw
In response to How to re-sort a sorted query?  ("Yudie" <yudie@axiontech.com>)
Responses Re: How to re-sort a sorted query?
List pgsql-sql
On Tue, 2004-10-26 at 14:23 -0500, Yudie wrote:
> I have a query that need to be sorted in order of price of store's
> product with unique store number.
>  
> Here is a sample data of storeproduct table:
>  
>  
> ItemSku , StoreNumber , Price
> ==========================
> 10001 , 7 , 30.00
> 10001 , 7 , 35.00 <-- duplicate store number 
> 10001 , 5 , 45.00
> 10001 , 2 , 50.00
>  
> Then I do this query to get unique store number and also the cheapest
> price from each store:
>  
> SQL= "Select distinct on (storenumber), itemsku, storenumber,price
> from storeproduct where itemsku='10001' 
> order by storenumber, price"

That won't get you the cheapest price, just an arbitrary one determined
by the physical storage order.

You need to use GROUP BY with an aggregate function:

SELECT itemsku, storenumber, MIN(price) FROM storeproduct WHERE itemsku = '10001' GROUP BY itemsku, storenumber ORDER
BYprice, storenumber;
 

> Result #1:
> ItemSku , StoreNumber , Price
> 10001 , 2 , 50.00
> 10001 , 5 , 45.00
> 10001 , 7 , 30.00
>  
> The question is how to make the query that returns as above but sorted
> by price?

The literal answer to your question is to put price first in the ORDER
BY clause, but I'm not convinced you actually want to know something
that simple.

-- 
Oliver Elphick                                          olly@lfix.co.uk
Isle of Wight                              http://www.lfix.co.uk/oliver
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========================================   "Whosoever therefore shall be ashamed of me and of my      words in this
adulterousand sinful generation; of him     also shall the Son of man be ashamed, when he cometh      in the glory of
hisFather with the holy angels."                                     Mark 8:38 
 



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