title: How do a case-insenstive Where clause in LINQ-to-NHibernate with the Oracle provider?
body: <p>For example, given the following code, how is it possible to make the string comparison case-insensitive?</p>
  
  <pre><code>        var query = from employeeGroup in _session.Linq&lt;EmployeeGroup&gt;()
                      from employee in employeeGroup.Employee
                      where employee.UserName == username
                      select employeeGroup.EmployeeGroupName;
  </code></pre>
  
  <p>The NHibernate.Linq.SqlClient.SqlClientExtensions.Upper() method might help but this only seems to be available with SQL Server.</p>
  
  <p>If I use the System.String class to do the comparison, I get an error: "Cannot use subqueries on a criteria without a projection.".  I believe this is because there is no direct mapping that NHibernate can do to SQL.</p>