title: Delete records from multiple tables
body: <p>Consider these several tables:</p>
  
  <pre><code>tab1
  -------
  userid
  email
  address
  environment
  
  tab2
  
  -------
  ecode
  company
  policy
  
  tab3
  -------
  id
  pan no.
  dl no.
  </code></pre>
  
  <p>Here <code>tab1</code> is the parent table. I want to delete all the <code>userid</code> of <code>tab1</code> from <code>tab2</code> and <code>tab3</code>. Either <code>userid</code> will be in <code>tab1</code> or <code>tab2</code> or both. These tables are environment specific means <code>environment/tab1</code> and <code>environment/tab2</code>.</p>
  
  <p>How can this be done with a single query?</p>