SQLite stores the data however you give it. I'm not aware of any documentation requiring that 9e999 be considered infinity, nor any requiring that the command line treat invalid numbers as null. Most likely, treating NaN as null is simply a way for the command line to behave reasonably in an otherwise undefined situation.
Practically, 9e999 is beyond the "infinity" limit for doubles on whatever compiler was used to build the command line. I think this limit is technically arbitrary, so on some compilers, either now, or in the future, 9e999 could very possibly NOT be infinity. std::numeric_limits<double>::max() should be a standard (read "safe") way of getting the "infinity" value in C++. In the Visual C++ 2005 compiler, the max double is 1.7976931348623158e+308. I'm not sure that this is constant however, so don't count on it. -----Original Message----- From: sqlite-users-boun...@sqlite.org [mailto:sqlite-users-boun...@sqlite.org] On Behalf Of Michael Chen Sent: Sunday, October 18, 2009 4:19 PM To: General Discussion of SQLite Database Subject: Re: [sqlite] Infinity I am looking for the answer too. anybody know it? On Sat, Oct 17, 2009 at 12:23 AM, Dan Bishop <danbisho...@gmail.com> wrote: > I've noticed that I can use IEEE Infinity values in SQLite by writing > any literal too big for a double. > > sqlite> CREATE TABLE foo (x REAL); > sqlite> INSERT INTO foo VALUES (9e999); -- +Inf > sqlite> INSERT INTO foo VALUES (-9e999); -- -Inf > sqlite> INSERT INTO foo VALUES (9e999 / 9e999); -- NaN: gets converted > to NULL > sqlite> .null NULL > sqlite> select * FROM foo; > Inf > -Inf > NULL > sqlite> SELECT * FROM foo WHERE ABS(x) = 9e999; > Inf > -Inf > > Is it true on all platforms that 9e999 = Infinity and CAST(9e999 AS > TEXT) = 'Inf'? What's the preferred SQL syntax for infinity? > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- Best regards, Michael Chen Google Voice Phone.: 847-448-0647 _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
