Your schema implies that there can be more than one TIME for any GNAME and AN
combination (otherwise the primary key would not need to include alle three
fields). This contradicts your statement that AN and TIME are "the same order".
(consider the tuples ("T1",1,1) and ("T2",1,2); the AN field compares equal, so
ORDER BY AN is free to return the T2 row before the T1 row).
Which query specifically would you have in mind that relies on your assertion?
Also, if your application requires that rows be returned in a specifc order,
your MUST specify this with en ORDER BY clause and not rely on the visitation
order. The visitation order may change due to a number of factors including the
SQLite version, the "shape" of your data, running ANALYZE and maybe more.
-----Ursprüngliche Nachricht-----
Von: sqlite-users [mailto:[email protected]] Im
Auftrag von [email protected]
Gesendet: Sonntag, 05. Mai 2019 21:56
An: [email protected]
Betreff: [EXTERNAL] [sqlite] If two orders are both the same order?
I have a schema with the following definition:
CREATE TABLE "XPOST"("GNAME" TEXT, "AN" INT, "TIME" INT, PRIMARY KEY
("GNAME", "AN", "TIME")) WITHOUT ROWID;
However, the order by "AN" and the order by "TIME" will be the same order.
(I also have a table "ART" where "AN" is the rowid, and again the order by
"TIME" will be the same order.)
How can you make SQLite to make that assumption in order to optimize the query?
(It should be done presumably without adding another index, since the data is
already in the correct order.)
(This is my "sqlnetnews" NNTP server software, which is public domain open
source. I don't know if maybe you might want to use NNTP for your mailing
lists?) _______________________________________________
sqlite-users mailing list
[email protected]
http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
___________________________________________
Gunter Hick | Software Engineer | Scientific Games International GmbH |
Klitschgasse 2-4, A-1130 Vienna | FN 157284 a, HG Wien, DVR: 0430013 | (O) +43
1 80100 - 0
May be privileged. May be confidential. Please delete if not the addressee.
_______________________________________________
sqlite-users mailing list
[email protected]
http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
