Minor Description
New function to_csv() should convert a column of StructType to a column with CSV string. The function should accept the CSV options as CSV data source does. API should expose the following methods:
def to_csv(e: Column, options: Map[String, String]): Column
and for Python/R:
def to_csv(e: Column, options: java.util.Map[String, String]): Column
Here is an example of usage:
select to_csv(named_struct('time', to_timestamp('2015-08-26', 'yyyy-MM-dd')), map('timestampFormat', 'dd/MM/yyyy'));
26/08/2015
