title: Using Limit random on mysql
body: <p>I just used this query</p>
  
  <pre><code>SELECT * FROM questions 
  ORDER BY RAND()
  LIMIT 20;
  </code></pre>
  
  <p>On mysql database I have a column called display (along with the  columns of questions)  where the values are equal to 1.So now as you can see in the query I have limited to 20.I want to change the value of the all the 20 to display=0.I know this is the query</p>
  
  <pre><code>update test3
  set display=0
  where id=11;
  </code></pre>
  
  <p>But this just sets the display of one row.How do I do it for the 20.
  Thanks in advance.</p>