title: copy data from one relation to another in PIG
body: <p>I have 2 relations:</p>
  
  <p>relation A: </p>
  
  <pre><code>101,Ankit-Reddy,08022017
  102,Siddarth-Battacharya,08022017
  103,Rajesh-Khanna,08022017
  </code></pre>
  
  <p>and Relation B:</p>
  
  <pre><code>102,Ronit-Roy,09022017
  103,Ranveer-Singh,09022017
  107,sadiya-some,09022017
  108,Raj-sharma,09022017
  </code></pre>
  
  <p>so in ID 102 and 103 in B holds different date and it is an existing record but 107,108 are new records so it will remain same.
  How can i update it to date in A.</p>
  
  <p>My final table should look like:</p>
  
  <pre><code>101,Ankit-Reddy,08022017
  102,Ronit-Roy,08022017
  103,Ranveer-Singh,08022017
  107,sadiya-some,09022017
  108,Raj-sharma,09022017
  </code></pre>
  
  <p>Any pig script for this.</p>