title: SQL Server add auto increment primary key to existing table
body: <p>As the title, I have an existing table which is already populated with 150000 records. I have added an Id column (which is currently null).</p>
  
  <p>I'm assuming I can run a query to fill this column with incremental numbers, and then set as primary key and turn on auto increment. Is this the correct way to proceed? And if so, how do I fill the initial numbers?</p>