title: SQL Server text file import error: The number of input columns cannot be zero
body: <p>I am having a problem with the SQL Server Import Wizard.  I am importing a text file without headers into an existing table (via append rows to the destination table).  On the text file, some of the columns at the end are NULL.  (Their corresponding columns in the table are nullable.)  On the Column Mappings step, the columns that are NULL do not appear in the mappings.  When the validations step occurs in the import, it throws the following error:</p>
  
  <p>Error 0xc020201b: Data Flow Task 3: The number of input columns for Destination 13 - some_table.Inputs[Destination Input] cannot be zero.
   (SQL Server Import and Export Wizard)</p>
  
  <p>Is this occurring because I haven't specified the mapping for the columns that are NULL?  If so, how do I specify them in the mapping?  I don't see a way to add columns other than the ones that the Wizard detects in the file.</p>