Postgres 9.6

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

create table conversation(
user_name varchar(200), 
employer_name varchar(200), 
message text, 
date_sent timestamp )
ALTER TABLE conversation ALTER COLUMN  
date_sent SET DEFAULT current_timestamp;
insert into conversation 
(user_name) values
('me');
1 rows affected

select * from conversation;


user_name
employer_name
message
date_sent


me
null
null
2022-04-01 09:38:13.674547