bcp to Export Empty String to NUL in Text File (Casuses issues to work with other systems)Posted: January 28, 2015
When you export data with bcp command, you may see some NUL value in the place of empty string. The workaround is to use NULL in TSQL to replace empty string with NULL by using NULLIF function.
Found the discussion here:
How to make Microsoft BCP export empty string instead of a NUL char?