PostgreSQL function returning multiple DIFFERENT datasets [duplicate] - sql

Question

Is it possible to return multiple result sets from a Postgres function, like in MSSQL:
CREATE PROCEDURE test
AS
SELECT * FROM first_table
SELECT * FROM second_table

Answer 1

A simpler way has been around since PostgreSQL 8.3:
CREATE FUNCTION test()
RETURNS SETOF first_table AS
$func$
BEGIN
RETURN QUERY
SELECT * FROM first_table;
RETURN QUERY
SELECT * FROM second_table; -- has to return same rowtype as first_table!
END
$func$ LANGUAGE plpgsql;
Call:
SELECT * FROM test();
Both result sets are appended to a single set returned from the function.
See the manual for RETURN QUERY.

Answer 2

CREATE OR REPLACE FUNCTION "pr_GetCustomersAndOrders"()
RETURNS SETOF refcursor AS
$BODY$DECLARE
customerRC refcursor;
orderRC refcursor;
BEGIN
open customerRC FOR
SELECT * FROM customers;
RETURN NEXT customerRC;
open orderRC FOR
SELECT * FROM orders;
RETURN NEXT orderRC;
RETURN;
END;$BODY$
LANGUAGE 'plpgsql' VOLATILE;
ALTER FUNCTION "pr_GetCustomersAndOrders"() OWNER TO postgres;
I.o.w. using refcursors :)

Answer 3

CREATE OR REPLACE FUNCTION public.TestReturnMultipleTales
(
param_coid integer,
ref1 refcursor,
ref2 refcursor
)
RETURNS SETOF refcursor
LANGUAGE 'plpgsql'
COST 100
VOLATILE PARALLEL UNSAFE
ROWS 1000
AS $BODY$
DECLARE
BEGIN
OPEN ref1 FOR SELECT * FROM dbo.tbl1 WHERE coid = param_coid;
RETURN NEXT ref1;
OPEN ref2 FOR SELECT * FROM dbo.tbl2 LIMIT 5;
RETURN NEXT ref2;
END;
$BODY$;
USE IN pgSQL Query:-
BEGIN;
SELECT football_players.show_cities_multiple(123456, 'Ref1', 'Ref2');
FETCH ALL IN "Ref1";
FETCH ALL IN "Ref2";
COMMIT;
SELECT football_players.show_cities_multiple(123456, 'Ref1', 'Ref2');
FETCH ALL IN "Ref1";
SELECT football_players.show_cities_multiple(123456, 'Ref1', 'Ref2');
FETCH ALL IN "Ref2";

Answer 4

If first_table and second_table have the same layout, you can also just use
SELECT * FROM first_table WHERE ...
UNION ALL
SELECT * FROM second_table WHERE ...
[EDIT: Thanks to a commenter (whose name is probably not "null" :) ) for pointing out that UNION ALL is faster than UNION.]

Answer 5

Yes.
Example:
test=# create function x () returns setof integer language plpgsql as $$ begin return next 1; return next 2; end $$;
CREATE FUNCTION
test=# select * from x();
x
---
1
2
(2 rows)
You can of course use an existing table/view or a custom type for the returned type.
Example using language SQL:
test=# create table customer (name varchar, birth_date date);
CREATE TABLE
test=# create function y () returns setof customer language sql as $$
select * from customer
union all
select * from customer
$$;
CREATE FUNCTION
test=# insert into customer values ('joe', now()::date);
INSERT 0 1
test=# insert into customer values ('jill', now()::date);
INSERT 0 1
test=# select * from y();
name | birth_date
------+------------
joe | 2009-04-16
jill | 2009-04-16
joe | 2009-04-16
jill | 2009-04-16
(4 rows)
See here for doc