The problem is not comparisons the problem is when I do something like this:
CREATE TABLE tb (a REAL);
INSERT INTO tb (a) VALUES(0);
UPDATE tb SET a = a + 5.45;
UPDATE tb SET a = a + 16.9;
SELECT a FROM tb;
Gives visually right answer: 22.35
But putting on a double variable gives me 22.3499948593433 (something like that)
and when declaring double a = 22.35 => gdb give me 22.3499999999999
Em 08/03/2013, às 14:11, Michael Black <mdblac...@yahoo.com> escreveu:
> Nobody should expect float comparisons like that to work.
> If they do they're asking for trouble.
> All you're seeing is what the database is letting you see. Their "0" is not
> really "0".
>
> Try this in your friendly C compiler
> main()
> {
> double d = 22.35-(5.45+16.9);
> printf("%f\n",d);
> printf("%g\n",d);
> printf("%e\n",d);
> }
> On both MS Visual C and gcc on a Linux system:
> 0.000000
> 3.55271e-015
> 3.552714e-015
>
> -----Original Message-----
> From: sqlite-users-boun...@sqlite.org
> [mailto:sqlite-users-boun...@sqlite.org] On Behalf Of Israel Lins
> Albuquerque
> Sent: Thursday, March 07, 2013 12:04 PM
> To: sqlite-users@sqlite.org
> Subject: [sqlite] Bug on real operations
>
> An example speaks more than words:
>
> Execute this:
> SELECT 22.35 - (5.45 + 16.9), 22.35 = (5.45 + 16.9), (5.45 + 16.9) - 22.35;
>
> The expected result on almost databases is:
> 0.0, true or 1, 0.0
>
> But in sqlite for some reason they are:
> 3.5527136788005e-15, 0, -3.5527136788005e-15
>
> I thing this can be a bug on calculation of doubles.
>
> Regards,
> Israel Lins Albuquerque
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