title: Converting SQL query into Doctrine, Error
body: <p>I am trying to convert a SQL query into a Doctrine QueryBuilder query. The SQL query works as I want it to within my SQL console (Workbench). But When I converted ,my SQl query into Doctrine 'Query' i get an error i cannot get my head around.....</p>
  
  <p>Pure SQL query:</p>
  
  <pre><code>    select 
  CONCAT('news/', feeds.slug, '/', articles.slug) as 'URL'
  
  from article_feeds
  left join articles on article_feeds.article_id=articles.id
  left join feeds on article_feeds.feed_id=feeds.id
  </code></pre>
  
  <p>DOCTRINE Query:</p>
  
  <pre><code>$stmt = $this-&gt;db-&gt;createQueryBuilder()
           -&gt;select('faf.article_id', 'faf.feeds_id')
           -&gt;addSelect('f.slug AS feedSlug')
           -&gt;addSelect('a.slug AS articleSlug')
           -&gt;addSelect("Group_CONCAT(DISTINCT CONCAT(feedSlug, '/' , articleSlug) SEPARATOR ',' ) AS url")
           -&gt;from('article_feeds', 'faf')
           -&gt;leftJoin('a', 'article_feeds', 'faf', 'af.article_id = a.id')
           -&gt;leftJoin('f', 'article_feeds', 'faf', 'af.article_id = f.id');
  
  
   $this-&gt;urls = $stmt-&gt;execute()-&gt;fetch(\PDO::FETCH_OBJ);
  </code></pre>
  
  <p>Error: </p>
  
  <pre><code>{
  code: 0,
  message: "The given alias 'articles' is not part of any FROM or JOIN clause table. The currently registered aliases are: faf."
  }
  </code></pre>
  
  <p>From What I understand there is a problem with my leftJoin's but why and what is it, how do I fix it.....?</p>