title: sql get query to get any student records who have passed multiple certificates?
body: <p>i have 3 mysql tables.</p>
  <ol>
  <li>certificates (certificate id, certificate name)</li>
  <li>students (student id, name)</li>
  <li>student certificates (id, student id, certificate id, reg_date)</li>
  </ol>
  <p>How can i construct a sql query to get any student records who have passed 20 certificates (base on 20 different certificate ids)?</p>
  <p>thank you</p>