title: pyspark join multiple conditions
body: <p>How I can specify lot of conditions in
  pyspark when I use <code>.join()</code></p>
  <p>Example :
  with hive :</p>
  <pre><code>query= &quot;select a.NUMCNT,b.NUMCNT as RNUMCNT ,a.POLE,b.POLE as RPOLE,a.ACTIVITE,b.ACTIVITE as RACTIVITE FROM rapexp201412 b \
      join rapexp201412 a where (a.NUMCNT=b.NUMCNT and a.ACTIVITE = b.ACTIVITE and a.POLE =b.POLE  )\
  </code></pre>
  <p>But in PySpark I don't know how to make it because the following:</p>
  <pre><code>df_rapexp201412.join(df_aeveh,df_rapexp2014.ACTIVITE==df_rapexp2014.ACTIVITE and df_rapexp2014.POLE==df_aeveh.POLE,'inner')
  </code></pre>
  <p>It does not work!!</p>