How to Return a Table That Was Created Within Function? - plpgsql

Question

I have a PL/pgSQL function that creates a table. I would like to return the table that was created as part of a "Return Table" function. Here is an example of the type of function I'm talking about:
CREATE OR REPLACE FUNCTION my_schema.new_foo_table(character varying)
RETURNS table(row_id bigint,
catalog_id varchar,
value numeric(5,4)) AS
$BODY$
DECLARE
v_table_name ALIAS FOR $1;
cmd text;
BEGIN
cmd := 'CREATE TABLE '||v_table_name||'
(row_id bigint,
catalog_id varchar,
value numeric(5,4))';
EXECUTE cmd;
cmd := 'INSERT INTO '||v_table_name||'
SELECT row_id, catalog_id, sum(value)
FROM other_table
GROUP BY row_id, catalog_id';
EXECUTE cmd;
RETURN --results of select * from v_table_name;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
How would I return the results of the new table I created? I'm guess the return would have to use some type of dynamic SQL "execute" statement since the name of the newly created table is in a variable.

Answer 1

Yes this can be done using RETURN QUERY EXECUTE 'command string'. For your example it would look like this:
CREATE OR REPLACE FUNCTION my_schema.new_foo_table(character varying)
RETURNS table(row_id bigint,
catalog_id varchar,
value numeric(5,4)) AS
$BODY$
DECLARE
arg_table_name ALIAS FOR $1;
v_table_name varchar;
cmd text;
BEGIN
v_table_name := quote_ident(arg_table_name);
cmd := 'CREATE TABLE '||v_table_name||'
(row_id bigint,
catalog_id varchar,
value numeric(5,4))';
EXECUTE cmd;
cmd := 'INSERT INTO '||v_table_name||'
SELECT row_id, catalog_id, sum(value)
FROM other_table
GROUP BY row_id, catalog_id';
EXECUTE cmd;
RETURN QUERY EXECUTE 'select * from v_table_name';
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
For additional information see section 40.6.1.2. in the POSTGRESQL documentation: http://www.postgresql.org/docs/9.3/static/plpgsql-control-structures.html#PLPGSQL-STATEMENTS-RETURNING