> On 04 Mar 2016, at 21:08, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> Alex Ignatov <a.ignatov@postgrespro.ru> writes:
>> Why string literal like 'Hello world!' doesnt automagicaly cast to text
>> type?
>
> Because it's not necessarily a string. It might be meant to be point,
> or json, or any number of other types.
>
>> Sure we can create our cast:
>> postgres=# create cast (unknown as text) with inout as implicit;
>> CREATE CAST
>
> That's a seriously bad idea; it will have all sorts of corner-case
> effects that you aren't expecting.
>
> There has been some talk of forcing unknown to text in the output
> columns of a sub-SELECT, which would fix the example you show with
> a lot less risk of side-effects elsewhere. But it's not exactly
> trivial because of interactions with INSERT ... SELECT.
>
> regards, tom lane
Oh! Thank you , Tom!