Обсуждение: Array of Arrays of int

Why does

select array(select array[1,2]);

give me an error: "could not find array type for data type integer[]"?

Is there a type-cast missing, or is this generally impossible? I was 
expecting something like

{{1,2}}

In my real-world application, the subquery returns more than one pair 
of ints, but I think it all boils down to this simpler example. I am 
using version 7.4 of PostgreSQL.

Thanks a lot,
Leo

Leo Fink <leo.fink@gmx.net> writes:
> Why does
> select array(select array[1,2]);
> give me an error: "could not find array type for data type integer[]"?

We don't do arrays of arrays.  You seem to be hoping for a 2-D array,
which is something fundamentally different (even though some programming
languages consider them the same ;-))
        regards, tom lane

Hello Tom.

Am 02.05.2005 um 06:11 schrieb Tom Lane:

> Leo Fink <leo.fink@gmx.net> writes:
>> Why does
>> select array(select array[1,2]);
>> give me an error: "could not find array type for data type integer[]"?
>
> We don't do arrays of arrays.  You seem to be hoping for a 2-D array,
> which is something fundamentally different (even though some 
> programming
> languages consider them the same ;-))

Actually, I don't. In my application I can work around the problem by 
using an array of string representations of these pairs, or by using 
two arrays of ints. I just thought that was less elegant and I was 
missing something obvious.

Thanks for your quick response.

Best,
Leo