title: I want to write a Hadoop MapReduce Join in Java
body: <p>I'm completely new in Hadoop Framework and I want to write a &quot;MapReduce&quot; program (HadoopJoin.java) that joins on x attribute between two tables R and S. The structure of the two tables is :</p>
  <pre><code>R (tag : char, x : int, y : varchar(30))
  and
  S (tag : char, x : int, z : varchar(30))
  </code></pre>
  <p>For example we have for <code>R table</code> :</p>
  <pre><code>r 10 r-10-0
  r 11 r-11-0
  r 12 r-12-0
  r 21 r-21-0 
  </code></pre>
  <p>And for S table :</p>
  <pre><code>s 11 s-11-0
  s 21 s-41-0
  s 21 s-41-1
  s 12 s-31-0
  s 11 s-31-1
  </code></pre>
  <p>The result should look like :</p>
  <pre><code>r 11 r-11-0 s 11 s-11-0
  
  etc.
  </code></pre>
  <p>Can anyone help me please ?</p>