title: spark drop multiple duplicated columns after join
body: <p>I am getting many duplicated columns after joining two dataframes,
  now I want to drop the columns which comes in the last, below is my printSchema</p>
  
  <pre><code>root
   |-- id: string (nullable = true)
   |-- value: string (nullable = true)
   |-- test: string (nullable = true)
   |-- details: string (nullable = true)
   |-- test: string (nullable = true)
   |-- value: string (nullable = true)
  </code></pre>
  
  <p>now I want to drop the last two columns </p>
  
  <pre><code> |-- test: string (nullable = true)
   |-- value: string (nullable = true)
  </code></pre>
  
  <p>I tried with df..dropDuplicates() but it dropping all </p>
  
  <p>how to drop the duplicated columns which comes in the last ?</p>