title: Delay or Wait-For Statement
body: <p>I have a 500,000 line SQL script:</p>
  
  <pre><code>update users set region_id = 9814746 where id = 101 and region_id is null;
  update users set region_id = 9814731 where id = 102 and region_id is null;
  update users set region_id = 3470676 where id = 103 and region_id is null;
  </code></pre>
  
  <p>I want to INSERT a delay of <code>10</code> seconds every <code>50</code> lines. Does <code>pgsql</code> have a <code>waitfor</code> statement like <code>t-sql</code>.</p>
  
  <p>Thanks.</p>