title: Using listagg with Polish characters
body: <p>I am having a little problem with 'listagg' function. I want to use it to concatenate rows into one string with comma as the separator. I managed to do it with this:</p>
  
  <pre><code>SELECT LISTAGG(U.name,', ') 
         WITHIN GROUP(ORDER BY NLSSORT(U.name,'NLS_SORT=polish'))
    FROM users U
    WHERE(U.birth_date BETWEEN :date1 AND :date2);
  </code></pre>
  
  <p>The problem is that Polish characters like 'ą','ę' etc. are not displayed correctly in the result. How can I fix that?</p>
  
  <p>Polish characters are not diplayed correctly in SQL Developer; for example I have users
  'Grzegorz Brzęcki-Dębina' and 'Paweł Kukiz', and in the output I get 
  'Grzegorz-Brz*cki-D*bina, Pawe* Kukiz'.</p>
  
  <pre><code>select name from users 
  </code></pre>
  
  <p>Displays it correctly. 
  Columns are NVARCHAR2.</p>
  
  <p>Man u are a genius :) That link helped a lot. All i need was: </p>
  
  <pre><code>SELECT LISTAGG(CAST(U.name AS VARCHAR2(10)),', ') 
         WITHIN GROUP(ORDER BY NLSSORT(U.name,'NLS_SORT=polish'))
    FROM users U
    WHERE(U.birth_date BETWEEN :date1 AND :date2);
  </code></pre>
  
  <p>Thx :)</p>