Thursday, 7 April 2016

Re: [firebird-support] VIEW optimization

 

Also consider the situation with multiple rows on the other side of the join: in that case the one side repeats as many times as there are rows

----- Bericht beantwoorden -----
Van: "'Mark Rotteveel' mark@lawinegevaar.nl [firebird-support]" <firebird-support@yahoogroups.com>
Aan: <firebird-support@yahoogroups.com>
Onderwerp: [firebird-support] VIEW optimization
Datum: do, apr. 7, 2016 19:31

For a join (inner join), the rows must exist in both tables, so both tables need to be evaluated.

Mark


----- Bericht beantwoorden -----
Van: "Gabor Boros gaborboros@yahoo.com [firebird-support]" <firebird-support@yahoogroups.com>
Aan: <firebird-support@yahoogroups.com>
Onderwerp: [firebird-support] VIEW optimization
Datum: do, apr. 7, 2016 19:06

2016. 04. 07. 18:48 keltezéssel, 'Mark Rotteveel' mark@lawinegevaar.nl  [firebird-support] írta: > Why wouldn't it be necessary, this is an inner join, so the joined table > needs to be evaluated if the matches row is present. >  > SELECT RDB$FIELD_NAME FROM VIEW1  SELECT RDB$FIELD_NAME FROM RDB$RELATION_FIELDS  For me the two SELECT is equal. Is not? I don't understand why the JOIN  is in the PLAN when not needed for the result. My original problem is... I have a complex SELECT and build up it at runtime in my application  include only the needed fields, JOINs in it. If create a VIEW from the  whole SELECT all JOIN etc executed even if only a single field needed  which can available without any JOIN or other thing.  Gabor   ------------------------------------  ------------------------------------  ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++  Visit http://www.firebirdsql.org and click the Documentation item on the main (top) menu.  Try FAQ and other links from the left-side menu there.  Also search the knowledgebases at http://www.ibphoenix.com/resources/documents/   ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ------------------------------------  Yahoo Groups Links  <*> To visit your group on the web, go to:     http://groups.yahoo.com/group/firebird-support/  <*> Your email settings:     Individual Email | Traditional  <*> To change settings online go to:     http://groups.yahoo.com/group/firebird-support/join     (Yahoo! ID required)  <*> To change settings via email:     firebird-support-digest@yahoogroups.com      firebird-support-fullfeatured@yahoogroups.com  <*> To unsubscribe from this group, send an email to:     firebird-support-unsubscribe@yahoogroups.com  <*> Your use of Yahoo Groups is subject to:     https://info.yahoo.com/legal/us/yahoo/utos/terms/

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Posted by: "=?utf-8?B?TWFyayBSb3R0ZXZlZWw=?=" <mark@lawinegevaar.nl>
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Visit http://www.firebirdsql.org and click the Documentation item
on the main (top) menu.  Try FAQ and other links from the left-side menu there.

Also search the knowledgebases at http://www.ibphoenix.com/resources/documents/

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