title: Using NVL with JOIN not returning the default value if null
body: <p>I have this query, just changed tables and columns name.</p>
  
  <pre><code>SELECT COM.NAME,
  COM.SURNAME,
  NVL(COM.ACCOUNT, -1) AS ACCOUNT,
  (SELECT NVL(BA.ACCOUNT_ID, '-1')
  FROM TABLE2 BA
  WHERE BA.ACCOUNT_ID = COM.ACCOUNT_ID) AS ACCOUNT_ID
  FROM TABLE1 COM
  WHERE COM.UNIQUE_DNI = 123123;
  </code></pre>
  
  <p>Search show the registry as:</p>
  
  <pre><code>NAME  ACCOUNT  ACCOUNT_ID
  qwe   -1
  </code></pre>
  
  <p>Im trying to make the -1 appear when BA.ACCOUNT_ID is null but with no success.</p>