Postgres 15

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CREATE TABLE phone_log(
  phone_log_id integer GENERATED ALWAYS AS IDENTITY PRIMARY KEY
, phone_number text NOT NULL
, area_code text
);

CREATE TABLE


INSERT INTO phone_log(phone_number, area_code)
SELECT nr, split_part(nr, '-', 1)
FROM  (
   VALUES
     ('310-430-9201')
   , ('917-829-2876')
   , ('424-917-1055')
   ) input(nr)
RETURNING *;


phone_log_id
phone_number
area_code


1
310-430-9201
310

2
917-829-2876
917

3
424-917-1055
424



INSERT 0 3


CREATE TABLE phone_log2 (
  phone_log_id integer GENERATED ALWAYS AS IDENTITY PRIMARY KEY
, phone_number text NOT NULL
, area_code text  GENERATED ALWAYS AS (split_part(phone_number, '-', 1)) STORED
);

CREATE TABLE


INSERT INTO phone_log2 (phone_number)
VALUES
  ('310-430-9201')
, ('917-829-2876')
, ('424-917-1055')
RETURNING *;


phone_log_id
phone_number
area_code


1
310-430-9201
310

2
917-829-2876
917

3
424-917-1055
424



INSERT 0 3