title: Conditional Select from different tables
body: <p>I have a requirement : </p>
  
  <p>There is a column <strong>CNT</strong> from a table A .</p>
  
  <p>If the value of <strong>CNT > 0</strong></p>
  
  <p>I have to choose column  <strong>SERIAL</strong> and <strong>DESCRIPTION</strong></p>
  
  <p>from table B else <strong>SERIAL</strong> and  <strong>DESCRIPTION</strong></p>
  
  <p>from table C .</p>
  
  <p>How can I do this in Oracle </p>