title: listagg function throwing error ORA-01489: result of string concatenation is too long
body: <p>I am using listagg  after cte in stored proc. However, it is returning error ' ORA-01489: result of string concatenation is too long'. Below is my stored procedure.</p>
  
  <pre><code>CREATE OR REPLACE PROCEDURE sp_market
  IS
      Names VARCHAR2(32767);
  BEGIN
      WITH CTE(sqql) As 
      (
        SELECT   field_name sqql FROM   pld_medicare_config  
      )  
      SELECT listagg(sqql, ' UNION ALL ') within GROUP (ORDER BY 1) into Names   from CTE;      
  END sp_market;
  </code></pre>
  
  <p>In select query, field_name returns long texts. I believe this is because listagg is not able to handle long characters that is result of select statement. How is work around for this issue?</p>