title: Error: ORA-01789: query block has incorrect number of result columns
body: <p>I have two relational views.</p>
  
  <p>First view:</p>
  
  <pre><code>CREATE VIEW VIEW1
  AS
  SELECT T#,
  MAX(DECODE(LEG#,1,DEPARTURE)) ORIGIN,
  MAX(DECODE(LEG#,1,DESTINATION)) DESTINATION1
  FROM TRIPLEG
  WHERE T# IN
  (SELECT T# FROM TRIPLEG WHERE LEG# &lt; 3
  AND T# IN
  (SELECT T# FROM TRIPLEG GROUP BY T#
  HAVING COUNT(T#) &lt; 3)
  GROUP BY T#)
  GROUP BY T#
  ORDER BY T#;
  </code></pre>
  
  <p>Second view:</p>
  
  <pre><code>CREATE VIEW VIEW2
  AS
  SELECT T#,
  MAX(DECODE(LEG#,2,DESTINATION)) DESTINATION1
  FROM TRIPLEG
  WHERE T# IN
  (SELECT T# FROM TRIPLEG WHERE LEG# &lt; 3
  AND T# IN
  (SELECT T# FROM TRIPLEG GROUP BY T#
  HAVING COUNT(T#) &lt; 3)
  GROUP BY T#)
  GROUP BY T#
  ORDER BY T#;
  </code></pre>
  
  <p>I use
      SELECT * FROM VIEW1
      UNION ALL
      SELECT * FROM VIEW2</p>
  
  <p>And I got the error ORA-01789.</p>
  
  <p>What I want to achieve is</p>
  
  <pre><code>T#    |       ORIGIN   | DESTINATION1 | DESTINATION2
  ------------------------------------------------------
  1            abc            efg           hij
  </code></pre>
  
  <p>is what I create considered relational views?</p>