I'd like to have a function that acts as a row filter (that can
optionally expand each row into multiple rows), but I don't know how to
wangle this such that the output is not enclosed in parentheses, i.e.
what I'm getting now is a single column of a composite type instead of
multiple columns matching the original table layout.
Example:
CREATE TABLE sometable (key text, value real);
INSERT INTO sometable VALUES ('A', 1);
INSERT INTO sometable VALUES ('B', 2);
-- unrealistic demo filter function
CREATE OR REPLACE FUNCTION foo(arow sometable) RETURNS SETOF sometable AS $$
DECLARE
BEGIN
RETURN NEXT arow;
RETURN NEXT arow;
RETURN;
END;
$$ LANGUAGE plpgsql;
-- SQL front-end for filter function
CREATE OR REPLACE FUNCTION explode(sometable) RETURNS SETOF sometable as $$
SELECT * FROM foo($1) AS t;
$$ LANGUAGE SQL STRICT IMMUTABLE;
select explode(sometable.*) from sometable;
explode
-----------
(A,1)
(A,1)
(B,2)
(B,2)
Thanks,
Kevin
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