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From:Scott Haneda Date:May 11 2005 5:19am
Subject:Re: possible join
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on 5/10/05 8:29 PM, Peter Brawley at peter.brawley@stripped wrote:

> Scott,
> 
>> ...In part, my trouble is that I need to take the resuling zone from the
>> first
>> select and use that to determine the field name.
> 
>> I can easily do this in my code in 2 selects, but was hoping to be able to
>> get the price back in just one select, if possible...
> 
> If you have control over the data model, it would be good to change the
> structure of fedex_rates to (id int PK, zone int, weight int, price
> decimal(10,2)), getting rid of the denormalised z_* columns which are causing
> you problems. Then a one-stage query would just be SELECT price FROM
> fedex_rates WHERE zone=8 AND weight=12.
> 
> If you're stuck with the table structure you show, you're stuck with two
> queries. If these lookup tables aren't large, there's probably not much
> performance to be gained from hiding the two stages inside a stored procedure,
> but if you want a one-step, IMO that's the way to go.

Ok, I changed the tables around a little, I can not really do this all in
one table, since the data gets made new often by fedex, at any rate, (no pun
intended :-))...

mysql> describe fedex_zones;
+-------+---------+------+-----+---------+----------------+
| Field | Type    | Null | Key | Default | Extra          |
+-------+---------+------+-----+---------+----------------+
| id    | int(11) |      | PRI | NULL    | auto_increment |
| zip   | char(5) |      | UNI |         |                |
| zone  | char(2) |      |     |         |                |
+-------+---------+------+-----+---------+----------------+

mysql> describe fedex_rates;
+--------+---------------+------+-----+---------+----------------+
| Field  | Type          | Null | Key | Default | Extra          |
+--------+---------------+------+-----+---------+----------------+
| id     | int(11)       |      | PRI | NULL    | auto_increment |
| weight | int(11)       |      |     | 0       |                |
| zone   | int(11)       |      |     | 0       |                |
| price  | decimal(10,2) |      |     | 0.00    |                |
+--------+---------------+------+-----+---------+----------------+

so first, I need to get the zone I am in, which is a:
SELECT zone from fedex_zones where zip = 94947
> 8

If the result in that case is 8, then I can
select price from fedex_rates where zone = '8' and weight = '25'

For some reason, this join is still not screaming out at me, or maybe I have
it right, and my data is in duplication, any help is appreciated.
-- 
-------------------------------------------------------------
Scott Haneda                                Tel: 415.898.2602
<http://www.newgeo.com>                     Novato, CA U.S.A.


Thread
possible joinScott Haneda11 May
  • Re: possible joinPeter Brawley11 May
    • Re: possible joinScott Haneda11 May
      • Re: possible joinmfatene11 May
      • Re: possible joinPeter Brawley11 May
      • just hiUnknown Sender11 May
        • Re: just hiJohan Höök11 May
      • Re: possible joinHarald Fuchs11 May
        • Re: possible joinSGreen11 May
        • Re: possible joinPeter Brawley11 May
Re: just hiNestor Florez11 May