Postgres 11

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select version();

version

PostgreSQL 11.22 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 8.5.0 20210514 (Red Hat 8.5.0-20), 64-bit

SELECT 1

create table blogs
( blog_id  serial,
  blog_post text not null)

CREATE TABLE

insert into blogs
  (blog_post)
values
  ('abc'),
  ('x y z'),
  ('another blog post') ;

INSERT 0 3

select * from blogs ;

blog_id
blog_post

1
abc

2
x y z

3
another blog post

SELECT 3

ALTER TABLE blogs ADD published boolean DEFAULT FALSE NOT NULL

ALTER TABLE

select * from blogs ;

blog_id
blog_post
published

1
abc
f

2
x y z
f

3
another blog post
f

SELECT 3