title: How to concatenate the first and last value of field and hide a specific record in table group footer in IReport
body: <p>I have a table component which shows some records in a group of year like this</p>
  
  <p>For example:</p>
  
  <pre><code>Year   Month    SumMonth //group header
  2009   Jan      1000     //table details
         Feb      2000
         Mar      3000
  2009   xxxx     6000     //group year footer
  2010   Jan      1100     //table details
         Feb      1200
  2010   xxxx     2300     //group year footer
  </code></pre>
  
  <p>The "xxxx" part in the above table is which i need to modify.</p>
  
  <p>I want to display the format like this:</p>
  
  <p>"<strong>Jan-Mar</strong>"  (for 2010 is "<strong>Jan-Feb</strong>")</p>
  
  <p>The question is how to get the value of <strong>first month</strong> and <strong>last month</strong> and concatenate them into a variable (or not need to?), so that I can put it into footer?</p>
  
  <p>The other problem is that how can I hide the records in specific year?</p>
  
  <p>For example the final modified display may like this:</p>
  
  <pre><code>Year   Month     SumMonth //group header
  2009   Jan-Mar   6000     //group year footer
  2010   Jan       1100     //table details
         Feb       1200
  2010   Jan-Feb   2300     //group year footer
  </code></pre>
  
  <p>You can see the whole records in 2009 are hided in the above table.
  Which options or what expression should I set?</p>