Postgres 15

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create table example (
  id serial primary key,
  name text not null check(regexp_like(name, '[^[:space:]]'))
)

CREATE TABLE

insert into example(name) values ('test');

INSERT 0 1

insert into example(name) values ('');

ERROR:  new row for relation "example" violates check constraint "example_name_check"
DETAIL:  Failing row contains (2, ).

insert into example(name) values ('   ');

ERROR:  new row for relation "example" violates check constraint "example_name_check"
DETAIL:  Failing row contains (3,    ).

insert into example(name) values ('  test  ');

INSERT 0 1

insert into example(name) values (E'\n');

ERROR:  new row for relation "example" violates check constraint "example_name_check"
DETAIL:  Failing row contains (5, 
).

insert into example(name) values (E'\t');

ERROR:  new row for relation "example" violates check constraint "example_name_check"
DETAIL:  Failing row contains (6, 	).

select * from example

id
name

1
test

4
  test

SELECT 2