title: split an email list by delimiter returns more than expected number of rows
body: <p>I have the following schema and SQL script: <a href="http://www.sqlfiddle.com/#!4/9c7bb/9" rel="nofollow noreferrer">http://www.sqlfiddle.com/#!4/9c7bb/9</a>  </p>
  
  <pre><code>create table a(
   cond varchar2(400),
   email varchar2(400) 
  );
  insert into a values('CPU_consumption', 'name_1@email.com;name_2@email.com;name_3@email.com');
  insert into a values('number of processes', 'name_1@email.com');
  insert into a values('memory consumption', 'name_1@email.com;name_2@email.com;');
  
  SELECT 
   regexp_substr(email,'((.*?)*?)(;|$)',1,level,NULL,1) AS result
  FROM a
  WHERE cond = 'memory consumption'
  CONNECT BY level &lt; regexp_count(email,'((.*?)*?)(;|$)');
  </code></pre>
  
  <p>Result:</p>
  
  <pre><code>name_2@email.com
  name_2@email.com
  name_1@email.com
  name_2@email.com
  </code></pre>
  
  <p>Can anyone explain why the result is not only 2 rows with the email addresses?
  Why there is displayed the 2nd email; address twice and after that the required list?</p>