Problem in

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От Max Lipsky
Тема Problem in
Дата
Msg-id 2164C531-EAA3-4CAF-996F-FEB0E5F73B32@gmail.com
обсуждение исходный текст
Ответы Re: Problem in
Список pgsql-sql
Hi everyone!

I found an incomprehensible behavior of some functions in PostgreSQL 9.5.12 (for 10.6 working good). 

For example:

SELECT acos(
cos(radians(48.9193))
* cos(radians(48.9193))
* cos(radians(2.5431) - radians(2.5431))
+ sin(radians(48.9193))
* sin(radians(48.9193))
) as result;

This returned [22003] ERROR: input is out of range

But this one working good:

SELECT acos(
cos(radians(48.9192))
* cos(radians(48.9192))
* cos(radians(2.5431) - radians(2.5431))
+ sin(radians(48.9192))
* sin(radians(48.9192))
) as result;

The difference is 48.9193 => 48.9192

I did research a bit and found what this query

SELECT cos(0.8538028527708621) * cos(0.8538028527708621) + sin(0.8538028527708621) * sin(0.8538028527708621) as s1;
Returned 1.0000000000000002

SELECT cos(0.8538028527708621) * cos(0.8538028527708621) as s1; -- 0.43180849723816966
SELECT sin(0.8538028527708621) * sin(0.8538028527708621) as s1; -- 0.5681915027618305
Looks like cos() have scale = 17 (sometimes), but sin() have scale 16



P.S. I saw it only in the IntelliJ IDEA console. In the native console these values will be rounded:

SELECT cos(0.8538028527708621) * cos(0.8538028527708621) as s1;
        s1
------------------
 0.43180849723817



* * *
Best Regards,
Max Lipsky

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