title: DataTable.Select expression fails using DateTime equals filter
body: <p>I have some data retrieved from a database which I hold in a data table. 
  What I want to do is extract only records that have a match to the date passed as a parameter only if it's greater than DateTime.MinValue(). This should be easy.</p>
  
  <p>Below is the code snippet of how I build the query string. I know that if I don't have the date filter I get 'x' records but I always get 0 with the date filter.</p>
  
  <pre><code>    string query = string.Format("Field_Name IN( 'GENDER','DOB','MARITAL_STATUS','SS') AND DIFF_TYPE = 'PER' AND Person_ID = '{0}'", Person_ID);
  
      if (ChangeDetected &gt; DateTime.MinValue)
      {
          query += string.Format(" AND ChangeToDT = #{0}#", ChangeDetected);
      }
  
      ChangeDataSet.DifferencesRow[] perChanges = this.m_ChangeDS.Differences.Select(query, "ChangeFromDT ASC, Field_Name DESC") as ChangeDataSet.DifferencesRow[];
  </code></pre>
  
  <p>I have tried all sorts of variations on outputting format for the DateTime in the filter but they all have the same result.</p>
  
  <p>I don't know enough LINQ to do the conditional filter that way either. {:o(</p>