How to assign result of table function to variable in PL/pgSQL - sql

Question

Assume I have the following function declaration:
CREATE OR REPLACE FUNCTION build_org_branch(IN p_org_id organization.org_id%type,
IN p_padding text)
RETURNS table
(
object_id int,
parent_id int,
name text
)
Then I want to call build_org_branch with parameters and assign it to a variable inside of another function like this:
declare
l_table record[]; --??????
begin
l_table := build_org_branch(1, ' '); -- is it okay?
if l_table is not null then
-- do stuff with table rows
end if;
end;
Or should I use some another approach to pass tables of rows?

Answer 1

You have built a function that returns a table, so process the results that way.
do $$
declare
rec record;
begin
for rec in (select * from build_org_branch(101, ''))
loop
raise notice 'Returned Row: object_id=>%, name=>%, parent_id=>%'
, rec.object_id
, rec.name
, rec.parent_id ;
-- do stuff with table rows
end loop;
end;
$$;
I do not have your table, so I'll hard code some values but how they are populated is not the issue, but what you do afterward. See fiddle.

Answer 2

Postgres doesn't support table's variables. If you can pass a some relational content, then a) you can use a temporary table or b) you can pass a array of composite values:
CREATE TYPE branch_type AS
(
object_id int,
parent_id int,
name text
)
CREATE OR REPLACE FUNCTION build_org_branch(IN p_org_id organization.org_id%type,
IN p_padding text)
RETURNS branch_type[] AS ...
and then you can write
declare
l_table branch_type[];
begin
l_table := build_org_branch(1, ' ');
if l_table is not null then
-- do stuff with table rows
end if;
end;
This is array to array assignment. Table to array is possible too, but always it has to be static typed.
CREATE OR REPLACE FUNCTION build_org_branch(IN p_org_id organization.org_id%type,
IN p_padding text)
RETURNS SETOF branch_type AS ...
and processing:
declare
l_table branch_type[];
begin
l_table := ARRAY(SELECT build_org_branch(1, ' '));
if l_table is not null then
-- do stuff with table rows
end if;
end;
For smaller number of rows (to ten thousand) a arrays should be preferred. For high number of rows you should to use temp table.