Subject Re: [firebird-support] VIEW optimization
Author Mark Rotteveel
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.

Mark


----- Bericht beantwoorden -----
Van: "Gabor Boros gaborboros@... [firebird-support]" <firebird-support@yahoogroups.com>
Aan: <firebird-support@yahoogroups.com>
Onderwerp: [firebird-support] VIEW optimization
Datum: do, apr. 7, 2016 18:34

Hi All,

VIEW:
CREATE VIEW VIEW1 AS
SELECT RDB$RELATION_FIELDS.RDB$RELATION_NAME, RDB$FIELD_NAME FROM 
RDB$RELATION_FIELDS
JOIN RDB$RELATIONS ON
RDB$RELATION_FIELDS.RDB$RELATION_NAME=RDB$RELATIONS.RDB$RELATION_NAME;

SELECT:
SELECT RDB$FIELD_NAME FROM VIEW1

PLAN:
PLAN JOIN (VIEW1 RDB$RELATION_FIELDS NATURAL, VIEW1 RDB$RELATIONS INDEX 
(RDB$INDEX_0))


Plan contains the JOIN but that not needed for the selected field. Is 
this an SQL standard thing or just Firebird's optimizer not smart enough?

Gabor


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