How to get unique values from list using only SQL

unique-values.sql

-- Postgres lets you create a 'constant table' that can be used in a query without actually persisting it
-- Source: https://www.postgresql.org/docs/current/queries-values.html

-- There's a couple ways we can use it:

WITH ages (id) AS (VALUES (13), (21), (32), (32), (78), (78))
SELECT DISTINCT id from ages;

SELECT DISTINCT id
FROM (VALUES (13), (21), (32), (32), (78), (78)) ages (id);

-- Or with more columns:
WITH users (id, name, age) AS (VALUES
	(1, 'Adam', 13),
	(2, 'Bertha', 21),
	(3, 'Charlie', 32),
	(4, 'Dabar', 32),
	(5, 'Erin', 78),
	(6, 'Flo', 78)
)
SELECT * FROM users;