title: Oracle SQL - Use coalesce when results is empty
body: <p>My query return different number of results eg.</p>
  <pre><code>Select ename from emp where job = 'MANAGER'; -- 3 rows
  </code></pre>
  <p>BLAKE
  CLARK
  JONES</p>
  <pre><code>Select ename from emp where job = 'ABC';  -- 0 rows
  </code></pre>
  <p>When use:</p>
  <pre><code>Select coalesce(max(ename),'-1') from emp where job = 'MANAGER';
  </code></pre>
  <p>Only return JONES,  Is it possible return all
  BLAKE
  CLARK
  JONES when result is not empty if empty return -1</p>