Re: Direct converting numeric types to bool

Thanks for your feedback!
Really, support migration from Oracle isn't the best argumentation for 
this patch.
Yes, in postgres already exists int::boolean casting and in case:

select 10::bigint::int::boolean;

it will perfectly work. But if you want to cast more significant number:

select (2^32)::bigint::int::boolean;

you receive the boundary value error.
Also in operations with floating-point numbers, may arise a fault in the 
results of calculations, because of which the number will always be cast 
in true
Thus it sounds like not a bad idea to support direct casting from 
numeric types to boolean. What do you think?

Alex Ignatov писал 2018-02-28 18:23:
> -----Original Message-----
> From: n.zhuchkov@postgrespro.ru [mailto:n.zhuchkov@postgrespro.ru]
> Sent: Wednesday, February 28, 2018 6:04 PM
> To: pgsql-hackers <pgsql-hackers@postgresql.org>
> Subject: Direct converting numeric types to bool
> 
> Attached patch allow direct convertion of numeric types to bool like
> integer::bool.
> Supported types:
>   - smallint;
>   - bigint;
>   - real;
>   - double precision;
>   - decimal(numeric).
> 
> This functionality is helped with migration from Oracle.
> 
> --
> Nikita Zhuchkov
> Postgres Professional: http://www.postgrespro.com The Russian Postgres
> Company
> 
> Hello!
> 
> What prevent us from:
> 
> postgres=# select 1::bigint::int::boolean;
>  bool
> ------
>  t
> (1 row)
> 
> It is just one additional casting and required no additional patching
> --
> Alex Ignatov
> Postgres Professional: http://www.postgrespro.com
> The Russian Postgres Company