title: Total zero count across all columns in a pyspark dataframe
body: <p>I need to find the percentage of zero across all columns in a pyspark dataframe. How to find the count of zero across each columns in the dataframe?</p>
  
  <p>P.S: I have tried converting the dataframe into a pandas dataframe and used value_counts. But inferring it's observation is not possible for a large dataset.</p>