title: primary key column needs to be Auto incremented in postgresql
body: <p>I have created a below table in postgresql:</p>
  
  <pre><code>create table retail_fact( id serial not null, name text);
  </code></pre>
  
  <p>I have customer table in hive and MySQL and I want to load the data from them to PostgreSQL <code>retail_fact</code> table using Pentaho pdi (connecting through presto). </p>
  
  <p>Also, O want the id to auto-increment in Postgres while I load the table with data from Hive and MySQL (in easier terms. i need an sql query to do the same).</p>
  
  <p>The query is something like below:</p>
  
  <pre><code>insert into postgresql.rpt.order_fact(
  
  select name from hive.retail.customer_hive
  UNION
  select name from mysql.retail.customer_mysql
  
  );
  </code></pre>
  
  <p>while i insert the above data for name column into order_fact in postgres, how do i make the id column auto increment?</p>