title: Hive String operator concatenate by || double pipe
body: <p>Language manual of Hive claims that double pipe string concatenation is supported, however I am unable to use this feature in my current version of HIVE 1.2.1000.2.4.3.6-2</p>
  
  <pre><code>hive&gt; select 'a'||'b';
  NoViableAltException(5@[323:1: atomExpression : ( ( KW_NULL )=&gt; KW_NULL -&gt; TOK_NULL | ( constant )=&gt; constant | castExpression | caseExpression | whenExpression | ( functionName LPAREN )=&gt; function | tableOrColumn | LPAREN ! expression RPAREN !);])
  </code></pre>
  
  <p>I was trying to find a version which starts to support that, but without any luck :-(  </p>
  
  <p>I know that I can use build in function concat to do the same thing, but I am rewriting bunch of Oracle views to Hive and I don't want to change things which can stay the same if possible. </p>