Re: Does Type Have = Operator?

On 05/12/2016 03:02 PM, Tom Lane wrote:
> "David E. Wheeler" <david(at)justatheory(dot)com> writes:
>> Some might argue that it ought to compare JSON objects, effectively be the equivalent of ::jsonb = ::jsonb, rather than ::text = ::text. But as Andrew points out to me offlist, “if that's what they want why aren't they using jsonb in the first place?â€
>> So I think that, up to the introduction of JSONB, it was important not to side one way or the other and put a JSON = operator in core. But now what we have JSONB, perhaps it makes sense to finally take sides and intoduce JSON = that does plain text comparison. Thoughts?
> Meh. Right now, if you want to compare values of type JSON, you have to
> either cast them to text or to jsonb, and that effectively declares which
> comparison semantics you want. I'm not sure that prejudging that is a
> good thing for us to do, especially when the argument that text semantics
> are what you would probably want is so weak.
>
> Andrew mentions in the extension you pointed to that providing a default
> comparison operator would enable people to do UNION, DISTINCT, etc on JSON
> columns without thinking about it. I'm not convinced that "without
> thinking about it" is a good thing here. But if we were going to enable
> that, I'd feel better about making it default to jsonb semantics ...
>

I think you've been a little liberal with quoting the docs ;-) The
reason I made it an extension is precisely because it's not
unambiguously clear what json equality should mean.

cheers

andrew