Re: CTE containing ambiguous columns

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> Suppose you do this:
> create table animals (id serial primary key, name varchar not null);

> Then you can do this:

> with beings as (select * from animals) select * from beings where id = 1;

> But not this:

> with beings as (select * from animals a1, animals a2) select * from
> beings where id = 1;

No different from

regression=# select * from (animals a1 cross join animals a2) x where id = 1;
ERROR: column reference "id" is ambiguous
LINE 1: ...ct * from (animals a1 cross join animals a2) x where id = 1;
^

There's no way to access the a1/a2 aliases here, either; and that rule
goes back to SQL92 or maybe further.

regards, tom lane