Re: "Cast" SRF returning record to a table type?

On Friday, April 17, 2015, Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com> wrote:

> I'm working on a function that will return a set of test data, for unit
> testing database stuff. It does a few things, but ultimately returns SETOF
> record that's essentially:
>
> RETURN QUERY EXECUTE 'SELECT * FROM ' || table_name;
>
> Because it's always going to return a real relation, I'd like to be able
> to the equivalent of:
>
> SELECT ... FROM my_function( 'some_table' )::some_table;

Unfortunately this means "cast the existing type to some_table" and
"record" is not a valid type in this context.

>
> Is there any trick that would allow that to work? I know that instead of
> 'SELECT * ...' I can do 'SELECT row(t.*) FROM ' || table_name || ' AS t'
> and then do
>
> SELECT ... FROM my_function( 'some_table' ) AS data( d some_table )
>
> but I'm hoping to avoid the extra level of indirection.
>
>
Haven't explored this specific code in depth...but which part - the
function alias or the select row(t.*)? They seem to be independent
concerns.

David J.