title: MySQL COUNT() across multiple columns
body: <p>I have been banging my head over this one for quite a while now but can not seem to get it working :(</p>
  
  <p>I have a table which among other standard fields, also has a few fields for different values of a same kind (INT for example). Value of each field is unique -> meaning if it appears in a <code>val_1</code> it will not appear in <code>val_2</code> and <code>val_n</code>. It can be however repeated in next row. My table looks something like this:</p>
  
  <pre><code>| id | val_1 | val_2 | val_3 | ... | val_n | some other stuff | ... |
  </code></pre>
  
  <p>My question is: How can I count occurrences of certain values in my table? For example: I would like to know which value occurs the most.</p>