title: merge tuple in Pig
body: <p>I have two sets of tuples and I want to inner join them by first element and merge other parts into one tuple, wondering how to implement this in Pig on Hadoop?</p>
  
  <p>Input two tuple sets,</p>
  
  <pre><code>1,(1,2)
  2,(2,3)
  
  1,(b,c,b,c)
  2,(c,d,c,d)
  </code></pre>
  
  <p>Expected output,</p>
  
  <pre><code>1,(1,2,b,c,b,c)
  2,(2,3,c,d,c,d)
  </code></pre>
  
  <p>thanks in advance,
  Lin</p>