title: Splitting row into multiple rows -- alternative to union?
body: <p>I know it can be done with union, but is kind of repetitive -- so is there a way to split multi column every row into multiple single column rows?</p>
  
  <p>Example:</p>
  
  <pre><code>SPLIT(SELECT col1,col2,col3 FROM tbl);
  </code></pre>
  
  <p>SPLIT is my imaginary function, for:</p>
  
  <pre><code>SELECT col1 FROM tbl
  UNION
  SELECT col2 FROM tbl
  UNION
  SELECT col3 FROM tbl;
  </code></pre>
  
  <p>So, is there such UNION/SPLIT equivalent?</p>