Generate fake data using generate_series in Postgresql

When read the book “Postgres for Data Architects”, in Chapter 4, the book use web2py to generate sample data. After wasting sometime on reading through the web2py api. I decide to use sql to generate the data directly.

CREATE TABLE account (id serial PRIMARY KEY ,
first_name varchar(100), last_name varchar(100), account_bal numeric (10,2));

INSERT INTO account(first_name, last_name, account_bal)
SELECT
  'first_' || seq  AS first_name,
  'last_' || seq  AS last_name,
   CASE (RANDOM() * 2)::INT
      WHEN 0 THEN 0
      WHEN 1 THEN 100
      WHEN 2 THEN 1000
   END
  as account_bal
FROM GENERATE_SERIES(1, 1000000) seq;

If better fake data is required, use Faker to generate the raw data and insert to db is a better option.

ref:

https://www.simononsoftware.com/generating-random-data-in-postgresql/ https://www.citusdata.com/blog/2018/03/14/fun-with-sql-generate-sql/ https://letstalkdata.com/2013/08/postgresql-generate_series-tricks/