title: How to count result from two columns in mysql
body: <p>I have a prediction table including homescore and awayscore. I want to output all distinct predictions and how many instances of each prediction exists.</p>
  
  <pre><code>matchid    homescore    awayscore
   1         1            2
   1         1            0
   1         9            3
   1         2            0
   1         1            2
   1         1            0
   2         3            2
   2         2            2
  ...
  </code></pre>
  
  <p>I want this to output a table like this for matchid 1:</p>
  
  <pre><code>result    predictions
  1-2       2           
  1-0       2
  9-3       1
  2-0       1
  </code></pre>