title: SQL statement that shows at least 16 courses not taken
body: <p>I have four schemas:</p>
  
  <pre><code>takes(ID,course_id,sec_id,semester,year)
  student(ID,name,dept_name,tot_credit)
  course(course_id,title,dept_name,credits)
  department(dept_name,building,budget)
  </code></pre>
  
  <p>I want to create a query that finds the name and id of each Astronomy student whose name begins with the letter ’T’ and who has not taken at least 16 Astronomy courses.</p>
  
  <p>What's the easiest way I could do this?</p>
  
  <p>I already wrote this beginning bit</p>
  
  <pre><code>SELECT name, id
  FROM student
  WHERE dept_name='Astronomy' AND name LIKE '%T%'
  </code></pre>
  
  <p>I'm not quite sure how to finish this off.</p>
  
  <p>Any help would be greatly appreciated :)</p>
  
  <p>Here's the result</p>
  
  <pre><code>NAME                 ID    CLASS_TAKEN
  -------------------- ----- -----------
  Tolle                38279          12 
  Teo                  62268          13 
  Tolle                93223          13 
  Tsukamoto            17707           5 
  Titi                 11576           9 
  Teo                  91772          12 
  Toraichi             50387          11 
  Tewari               80754          14 
  Tiroz                64091          14 
  
   9 rows selected 
  </code></pre>
  
  <p>I need Teo with the id 91772 and Tewari 80754 to be gone</p>