title: add a column to a table with 4 possible default value based on logical argument
body: <p>How can I add a column to a table with the number 1 to 4 based on each row meeting certain criteria?</p>
  
  <p>Suppose I have a table:
  <a href="http://i.stack.imgur.com/yoFEj.png" rel="nofollow">Like this</a> 
  with two columns (ID) and (RESULTS) and that I want to add a third column called (SCORE).</p>
  
  <p>I want to give a score (between 1 and 4) to each row in my column based on whether the numbers in column (RESULTS) meet certain criteria.</p>
  
  <p>If the RESULT is negative, I want to give it a score of 1,
  If the RESULT is less than 30, a score of 2,
  less than 100 a score of 3
  and greater than 100 a score of 4</p>
  
  <p>I have tried using the CASE statement but cannot seem to get it to work;
  I searched on the topics about constraints but they always seem to have two arguments - I need 4</p>