title: MySQL SELECT DISTINCT multiple columns
body: <p>Let's say I have columns <code>a, b c, d</code> in a table in a MySQL database. What I'm trying to do is to select the distinct values of ALL of these 4 columns in my table (only the distinct values). I tried stuff like:</p>
  
  <pre><code>SELECT DISTINCT a,b,c,d FROM my_table;
  SELECT DISTINCT a,b,c,d FROM my_table GROUP BY a,b,c,d;
  </code></pre>
  
  <p>None of those worked. Can anybody help out here?</p>
  
  <p>Thank you</p>
  
  <p><strong>NOTE</strong> I want the distinct values of the columns <code>a, b, c d</code> separately. Not the distinct combination of values</p>