title: Rows.Count = 1 when returned dataset consists of an empty row
body: <p>My query does not return anything but an empty row, since there is no records that meet all the criteria of my query. However, Rows.Count is 1 instead of 0. Here is my query:</p>
  
  <pre><code>SELECT LicenseID 
  FROM LICENSES 
  WHERE LicenseType = @LicenseType 
      AND DriverID = @DriverID 
      AND CarID IN(
          SELECT CarID 
          FROM CARS 
          WHERE CarSerial = @CarSerial 
              AND DriverID = @DriverID
      ) AND LicenseID IS NOT NULL 
      AND ((StartDate &lt;= CONVERT(DATETIME, @EndDate)) 
      AND (EndDate &gt;= CONVERT(DATETIME, @StartDate)))
  </code></pre>
  
  <p>Here is my C# if statement condition that for some reason keeps being true due to row count, even though there is no record meeting criteria:</p>
  
  <pre><code>if (ds != null &amp;&amp; ds.Tables[0].Rows.Count &gt; 0)
  </code></pre>
  
  <p>The database used is SQL Server. This previously seemed to work correctly under Oracle.</p>