| From: | Martijn van Oosterhout <kleptog(at)svana(dot)org> |
|---|---|
| To: | Vincenzo Romano <vincenzo(dot)romano(at)gmail(dot)com> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Using the query INTERSECTion |
| Date: | 2007-06-18 17:27:35 |
| Message-ID: | 20070618172735.GD24080@svana.org |
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| Lists: | pgsql-general |
On Mon, Jun 18, 2007 at 04:10:41PM +0200, Vincenzo Romano wrote:
> Hello everyone.
>
> In order to build some dynamic queries (EXECUTE under PL/PgSQL)
> I'm taking in consideration to use the INTERSECT operator in order
> to split a WHERE-condition in a static one and a dynamic one to be
> built at runtime.
The INTERSECT will almost certainly be slower, basically because all
the joins will have to be processed twice. Also, the results won't be
quite the same, especially with respect to duplicate records and NULLs.
Have a nice day,
--
Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.
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