Q:

Use Record As Function Argument in RETURNING Statement

I have a plpgsql function that takes a record as an argument.
I would like to call this function in the RETURNING statement of an insert, but am unsure what to put as the argument (* does not work) i.e.,
-- Postgres 12

INSERT INTO some_table (a, b, c)
VALUES .....
RETURNING
function_that_takes_record_argument(<the_new_record>)

What can I use in place of <the_new_record>?

A:

To pass a record/row to a function you need to explicitly specify the record type:
create table t(a int, b text);

create or replace function f(r record) returns int language plpgsql as $$
begin
    return r.a;
end $$;

insert into t values(2, 'b');

select f(t.*), f(t), f((a,b)::t) from t;

 f | f | f 
---+---+---
 2 | 2 | 2

insert into t values(3, 'c') returning f(t);

 f 
---
 3

