title: Parameterized query and NULL DateTime value
body: <p>I'm working a program that is pulling a string field from an access database, separating out a name (first and last) from a date then save the name separately from the date in a different access database. </p>
  
  <p>I've got everything done except some of the date values are null so I need to parametrize the SQL but I haven't been able to figure out how to do make the parametrization work.</p>
  
  <p>I've put in dummy values for the variable and it adds them to the table just fine. I've cut out the other variables in the code snippet below since they're all repeats of what's there. os is a list holding data from a structure.</p>
  
  <pre><code>string sqlcmd = "INSERT INTO signatures VALUES ('" + os.QASignature + "', 'QADate = @QADATE'";
  System.Data.OleDb.OleDbCommand SQLCommand = new System.Data.OleDb.OleDbCommand(sqlcmd, Connection);
  using (SQLCommand)
  {
      SQLCommand.Parameters.Add("@QADATE", System.Data.OleDb.OleDbType.Date).Value = os.QADate;
      SQLDataReader = SQLCommand.ExecuteReader();
  }
  </code></pre>