Hi all,
I am interested in figuring out how to get the names and types of the columns
from an arbitrary query. Essentially, I want to be able to take a query like:
CREATE TABLE foo(
bar bigserial,
baz varchar(256)
);
SELECT * FROM foo WHERE bar = 42;
and figure out programmatically that the select will return a column "bar" of
type bigserial, and a column "foo" of type varchar(256). I would like this to
work for more complex queries as well (joins, CTEs, etc).
I've found https://wiki.postgresql.org/wiki/Query_Parsing, which talks about
related ways to hook into postgres, but that seems to only talk about the parse
tree — a lot more detail and processing seems to be required in order to figure
out the output types. It seems like there should be somewhere I can hook into
in postgres that will get me this information, but I have no familiarity with
the codebase, so I don't know the best way to get this.
How would you recommend that I approach this? I'm comfortable patching postgres
if needed, although if there's a solution that doesn't require that, I'd prefer
that.
Thanks,
:w
