title: Specifying columns in MINUS query yields different results from using *
body: <p>When I am executing </p>
  
  <pre><code>SELECT * FROM TABLE_NAME WHERE ROWNUM &lt;= 20 
  MINUS 
  SELECT * FROM TABLE_NAME WHERE ROWNUM &lt;= 10 
  </code></pre>
  
  <p>I get expected result of <code>SKIP</code> 10 <code>TAKE</code> 10 (ten rows)</p>
  
  <p>but if I specify columns explicitly</p>
  
  <pre><code>SELECT COL1, COL2, COL3 FROM TABLE_NAME WHERE ROWNUM &lt;= 20 
  MINUS 
  SELECT COL1, COL2, COL3 FROM TABLE_NAME WHERE ROWNUM &lt;= 10
  </code></pre>
  
  <p>I get single record back. (one row)</p>
  
  <p>Why does this happen? How can I fix this?</p>