This blog is intended to provide insight on some of the data encoding issues that you may encounter while using Polybase to load data to SQL Data Warehouse. This article also provides some options that you can use to overcome such issues and load the data successfully.
In most cases, you will be migrating data from an external system to SQL Data Warehouse or working with data that has been exported in flat file format. If the data is formatted using either the UTF-8 or UTF-16 encoding standard, you can use Polybase to load the data. However, the format of your data is dependent on the encoding options supported by the source system. Some systems do not provide support for UTF-8 or UTF-16 encoding. If the data you are working with is formatted in an alternate format, such as ISO-8859-1, then being able to convert the data to UTF-8/UTF-16 format can save valuable time and effort.
Read about it in the Azure blog.