Postgres 12

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select version();

version

PostgreSQL 12.14 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 8.5.0 20210514 (Red Hat 8.5.0-16), 64-bit

SELECT 1

create table  profiles_g (
   user_id      integer     not null primary key  
 , first_name   varchar(49) not null
 , last_name    varchar(49) not null 
 , display_name text generated always as (first_name || ' ' || last_name) stored 
);

CREATE TABLE

insert into profiles_g(user_id, first_name, last_name)
    values (1, 'George','Anderson')
         , (2, 'Paul', 'McCartney') ; 
select * from profiles_g;          

INSERT 0 2

user_id
first_name
last_name
display_name

1
George
Anderson
George Anderson

2
Paul
McCartney
Paul McCartney

SELECT 2

update  profiles_g
  set last_name = 'Harrison'
 where user_id = 1; 
select * from profiles_g;  

UPDATE 1

user_id
first_name
last_name
display_name

2
Paul
McCartney
Paul McCartney

1
George
Harrison
George Harrison

SELECT 2