Re: SELECT my_table.varchar FROM my_table

Richard Broersma <richard(dot)broersma(at)gmail(dot)com> writes:
> On Mon, May 31, 2010 at 7:48 AM, Jan Strube <js(at)deriva(dot)de> wrote:
>> I accidentally encountered a feature in Postgres 8.3 that I couldn't find in
>> the documentation while submitting a query like
>>
>> SELECT my_table.varchar FROM my_table
>>
>> which returns a concatenated string of all field values per row.
>> I wonder where this is documented (and if it has something to do with
>> composite types).
>>
>> Can anyone please explain?

> I don't really know, but the result looks more like a single field

It's equivalent to (my_table.*)::varchar. We've seen enough people
confused by this (or the equivalent cases with text and name as
the target type) that I wonder if we should intentionally break the
symmetry and disable treating this case as a cast. Although I do
rather wonder what the OP expected to happen here.

regards, tom lane