Re: Integer range?

On Oct 9, 2009, at 9:46 AM, Scott Ribe wrote:

> The range of a twos-complement 32-bit integer is -2147483648 through
> 2147483647. Yet in Postgres:
>
>
> # select -2147483647::int4;
>  ?column?
> -------------
> -2147483647
> (1 row)
>
> # select -2147483648::int4;
> ERROR:  integer out of range
>
>
> Is this a bug? Or something required by the SQL standard?

Neither, really. The cast shortcut you're using is binding to the
digits more tightly than the minus prefix.

So what you end up with is the integer 2147483648, with a unary minus
in front of it, pretty much like this:

# select -(2147483648::int4);
ERROR:  integer out of range

While what you want is more like this:

# select '-2147483648'::int4;
     int4
-------------
  -2147483648
(1 row)

# select cast(-2147483648 as int4);
     int4
-------------
  -2147483648
(1 row)

Cheers,
   Steve