On Mon, 25 Jun 2007 17:56:28 +0100
Gregory Stark <stark@enterprisedb.com> wrote:
>
> This seems odd. It's not deciding that it's ambiguous or coming from another
> datatype for which no implicit cast exists. It knows perfectly well that it
> wants to convert to text but fails?
>
>
> postgres=# select 'a'||b from (select 'b' as b) as x;
> ERROR: failed to find conversion function from unknown to text
It isn't the destination type that is the problem here but the source.
I suppose that it could default 'b' to text but really, that isn't
necessarily what '' signifies. How about '2007-06-25'? Is that text,
date or timestamp? Try this.
select 'a'||b from (select 'b'::text as b) as x;
--
D'Arcy J.M. Cain <darcy@druid.net> | Democracy is three wolves
http://www.druid.net/darcy/ | and a sheep voting on
+1 416 425 1212 (DoD#0082) (eNTP) | what's for dinner.