2016-10-16 21:05 GMT+02:00 Keith Medcalf <kmedc...@dessus.com>: > > See https://www.sqlite.org/optoverview.html > under section 10.0 Query Flattening > > Your query is: > > SELECT * FROM <view> WHERE <condition> > > which could be treated as > > SELECT * > FROM (view select statement) > WHERE condition > > and then flattened. Note however that the query WILL NOT be flattened > because of rule #2, the subselect in the FROM clause contains an aggregate ...
OK, I understand. The query is mostly run in a cron job. So I think I go for the ‘expensive’ one, because that is more clear. >> -----Original Message----- >> From: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org] >> On Behalf Of Jens Alfke >> Sent: Sunday, 16 October, 2016 12:17 >> To: SQLite mailing list >> Subject: Re: [sqlite] Why takes the second SELECT three times as much >> time? >> >> >> > On Oct 16, 2016, at 4:49 AM, Luuk <luu...@gmail.com> wrote: >> > >> > Because your second query has to build the complete view before it can >> decide if a result is between the selected dates? >> >> I didn’t think a view had a physical manifestation that had to be built; I >> thought it was just a shortcut/macro for a nested SELECT statement. >> Or is the query optimizer not able to convert the nested SELECT into the >> same form as the first query? >> >> —Jens >> _______________________________________________ >> sqlite-users mailing list >> sqlite-users@mailinglists.sqlite.org >> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > > > > _______________________________________________ > sqlite-users mailing list > sqlite-users@mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users -- Cecil Westerhof _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
