title: sql select condition, if col1 empty check on col2
body: <p>How could I achieve the following in SQL. (I have trouble with the checking if <code>col1</code> is empty, check if <code>col2</code> is <code>"confirmed"</code>)</p>
  
  <p><code>select data from table1 where col1 = "true"</code> or (if <code>col1</code> is empty, check <code>col2 = "confirmed"</code>). </p>
  
  <p>(the value to check for <code>col1</code> and <code>col2</code> are different)</p>