title: What is the difference between GROUP and COGROUP in PIG?
body: <p>I understood Group didn't work with multiple tuples and hence we had COGROUP in PIG. However, while checking today the GROUP command works for me. I am using PIG-0.12.0.
  My commands and outputs are as follows. </p>
  
  <pre><code>grunt&gt; grpvar = GROUP C by $2, B by $2;
  grunt&gt; cogrpvar = COGROUP C by $2, B by $2;
  grunt&gt; describe grpvar;
  
  grpvar: {group: chararray,C: {(pid: int,pname: chararray,drug: chararray,gender: chararray,tot_amt: int)},B: {(pid: int,pname: chararray,drug: chararray,gender: chararray,tot_amt: int)}}
  
  grunt&gt; describe cogrpvar;
  
  cogrpvar: {group: chararray,C: {(pid: int,pname: chararray,drug: chararray,gender: chararray,tot_amt: int)},B: {(pid: int,pname: chararray,drug: chararray,gender: chararray,tot_amt: int)}}
  </code></pre>
  
  <p>Is GROUP expected to work like this? 
  What is the difference between GROUP and COGROUP them?</p>