SQL

postgresql default value boolean

ALTER TABLE users
  ADD COLUMN "priv_user" BOOLEAN NOT NULL DEFAULT FALSE;

postgres set default value

ALTER TABLE ONLY users ALTER COLUMN lang SET DEFAULT 'en_GB';

postgresql default value

CREATE TABLE products (
    product_no integer,
    name text,
    price numeric DEFAULT 9.99
);

postgres default value

ALTER TABLE your_tble ADD COLUMN your_col VARCHAR(8) DEFAULT 'sometext';