title: Get records containing iframe elements with 'src="http:' with PostgreSQL
body: <p>I need to get all records with iframe elements with the attribute "src" starting with "http:".</p>
  
  <p>e.g.</p>
  
  <p>In table "entries" there is a column "content", which contains HTML strings. These strings may contain zero or more iframe elements.</p>
  
  <p>If inside "content" a record has something like this:</p>
  
  <pre><code>&lt;iframe title="Some title" src="http://webpage.com" /&gt;
  </code></pre>
  
  <p>It should be returned.</p>
  
  <p>I'm currently trying with the next query but results are not as expected.</p>
  
  <pre><code>SELECT content FROM entries WHERE content ~ '.*&lt;iframe.*src="http:.*'
  </code></pre>