title: How to give condition for null values of multi select parameter in Ireport?
body: <p>I am developing a report using <a href="http://en.wikipedia.org/wiki/JasperReports#Third-party_tools" rel="nofollow">iReport</a> where I want to add a condition for null values. It's working with single select option as:</p>
  
  <pre><code>(city=$P{p_city} or $P{p_city} is null)
  </code></pre>
  
  <p>It means here if we do not pass any value for the city parameter, the report will work, but this is not working in case of a multiselect option. We have to choose a "Collection" value expression in iReport when we create a parameter:</p>
  
  <pre><code>($X{IN, country,p_country} or $P{p_country} is null) 
  </code></pre>
  
  <p>I have created two input controls in <a href="http://en.wikipedia.org/wiki/JasperReports#Jaspersoft" rel="nofollow">JasperReports Server</a> to run this report. One is a single select, "Select City" and the other is a multi select, "Select country", and the report is running without passing a value for the "Select city" parameter, but for the "select country" parameter, we must pass the value, because "Select country" is multi select and a Collection type parameter and you can not add null condition in a query as for the city parameter.</p>
  
  <p>How we can modify the <a href="http://en.wikipedia.org/wiki/JasperReports#JRXML" rel="nofollow">JRXML</a> query?</p>