> No.
yes, read on :)
> I had a view called "Web_User":
>
> Select fields from tableA, tableB, tableC where clause
>
> I had another view:
>
> Select fields from tableD, web_user where field_in_web_user =
> something
>
> And it was extremely slow. However, doing this:
>
> Select fields from tableD, tableA, tableB, tableC where
> clause and field_in_tableB = something
>
> Was vastly quicker.
duh :) You use a join in the latter, and a subquery in the former. This
COULD lead to different execution plans. The first
query will become:
SELECT fields FROM TableD, (SELECT fields from table a, tableb, tablec where
clause) Web_user WHERE field_in_web_user = something
your second query is completely different, as you optimized it. It will
be even faster if you move the the AND clause to an
INNER JOIN ON's clause I think. That doesn't mean what I said was wrong, you
just compared apples with oranges (sorry)
FB
>
> -----Original Message-----
> From: Discussion of advanced .NET topics.
> [mailto:[EMAIL PROTECTED] On Behalf Of Frans Bouma
> Sent: Friday, 11 August 2006 22:13
> To: [email protected]
> Subject: Re: [ADVANCED-DOTNET] SQL Server 2005 Xml question...
>
> > In my experience, that's not correct.
>
> so, if I have a view, CustomersView SELECT * FROM Customers
>
> and I have 2 queries:
> A:
> SELECT * FROM CustomersView
> WHERE Country='USA'
>
> B:
> SELECT * FROM (SELECT * FROM Customers) CustomersView WHERE
> CustomersView.Country = 'USA'
>
> You're saying A is slower than B?
>
> Check the execution plans. Most modern RDBMS's will
> merge the SQL of the view into the query first, then
> calculate the execution plan and then execute it. So a view
> is more or less just a code snippet.
>
> It will be different with indexed views which are
> stored results and act as tables, there the view usage is
> much faster, as the query of the view is bypassed as the
> results are used directly
>
> FB
>
>
> >
> > -----Original Message-----
> > From: Discussion of advanced .NET topics.
> > [mailto:[EMAIL PROTECTED] On Behalf Of
> Frans Bouma
> > Sent: Friday, 11 August 2006 19:13
> > To: [email protected]
> > Subject: Re: [ADVANCED-DOTNET] SQL Server 2005 Xml question...
> >
> >
> > A view is just a query, so a query utilizing a view isn't
> > going to be slower than a query with the view's sql inside it.
> >
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