Re: Record with a field consisting of table rows

On 15 Jan 2011, at 21:57, Jon Smark wrote:

>> No, of course not. A function cannot return different
>> amounts of different return-values in any language I know
>> of.
>
> Come on, you make it sound like it's something inconceivable or exotic,
> even though pretty much any strongly-typed language with a post-1970s
> type-system will allow a function to return tuples of arbitrary values.
> Have you never come across Ocaml, Haskell, Scala, and so forth?

A tuple wouldn't be unusual, but you're not asking for a simple tuple here. What you're asking for is a value and a set of tuples. That would sort of look like this:

total | users
---------------------------------------------------------
3 | foo
| bar
| baz

And what's worse, after the first returned tuple you only seem to want the users value, without the total value. I don't know of any language that can do that and I'm pretty sure the languages you mentioned can't do that either. It makes parsing the return values unnecessary difficult, I bet that's a compelling enough reason that nobody seems to have implemented it.

What most languages, including pgsql, _can_ do is this:

total | users
---------------------------------------------------------
3 | foo
3 | bar
3 | baz

Or this:

total | users
---------------------------------------------------------
3 | [foo, bar, baz]

Alban Hertroys

--
Screwing up is an excellent way to attach something to the ceiling.

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