title: Insert consecutive numbers into a table
body: <p>Let's say I have the following table:</p>
  
  <pre><code>id     name     age
         John     23
         Mary     22
         Mike     25
         etc      etc
  </code></pre>
  
  <p>I would like to generate consecutive number into <code>id</code> column for every record. Could anyone help me?</p>
  
  <p>Sorry if I asked the same question as asked before.</p>