Re: SQL Join - MySQL/PostgreSQL difference?

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От Ian Harding
Тема Re: SQL Join - MySQL/PostgreSQL difference?
Дата
Msg-id 3A7A3B4C.856EC9EF@pakrat.com
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Ответ на SQL Join - MySQL/PostgreSQL difference?  (Brice Ruth <brice@webprojkt.com>)
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Brice Ruth wrote:

> Greetings.
>
> I'm working with a product provided by a third part that interfaces to
> data housed in a database of your choice.  Previously, my choice was
> MySQL - apparently it handled certain queries too slowly, so I'm giving
> PostgreSQL a shot.  Here's the query:
>
> SELECT
>   a.Number,
>   a.Code,
>   a.Text
> FROM
>   b,
>   a
> WHERE
>   (b.Id = a.Id) AND
>   (VersionId = 'key1') AND
>   (Category = 'key2') AND
>   (b.d_Id = 'key3')
> ORDER BY
>   a.Number;
>
> (my apologies: I had to 'mangle' the table/column names because of NDA)
>
> So my question is this: would this query operate differently in MySQL
> than in PostgreSQL?  The reason I ask is that this query in MySQL
> returns results, yet in PostgreSQL it does not.  I read a post about
> PostgreSQL not supporting outer joins, but I don't have enough
> experience with SQL to determine if this is such a query or not.  Please
>
> advise.
>
> Any help will be (as always) sincerely appreciated.
>
> --
> Brice Ruth
> WebProjkt, Inc.
> VP, Director of Internet Technology
> http://www.webprojkt.com/

It should work the same in both.  The only thing I notice is that not all
the field names are qualified with table names or aliases.  That can lead
to ambiguity, but the query would blow up on both databases if that were a
problem.

Ian


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