Re: Do you know a json_populate_record alternative method to create a ROW with a named field notation?

=?UTF-8?Q?St=C3=A9phane_Klein?= <contact@stephane-klein.info> writes:
> **Question:** do you know a method like json_populate_record (
> https://www.postgresql.org/docs/13/functions-json.html), which allows
> creating a `ROW` with named field notation without using a json format?

You mean you want to give the field names explicitly in the expression?

The closest thing I can think of is to make a constructor function and
invoke it with named-argument notation:

regression=# CREATE TYPE contact AS (
regression(#    firstname VARCHAR,
regression(#    lastname VARCHAR
regression(# );
CREATE TYPE
regression=# create function make_contact(firstname varchar, lastname varchar)
regression-# returns contact as 'select row(firstname, lastname)::contact'
regression-# language sql;
CREATE FUNCTION
regression=# select make_contact(firstname => 'John', lastname => 'Doe');
 make_contact 
--------------
 (John,Doe)
(1 row)

A bit tedious to set up, but it would have some advantages, eg you
could provide default values.

            regards, tom lane