title: Display employee name,total salary of each employee(total salary=salary+commission)
body: <p>Display employee name, total salary of each employee.</p>
  
  <p><strong>Conditions:</strong></p>
  
  <ul>
  <li>if commission is <code>not NULL</code> then <code>total salary=(salary + commission)</code></li>
  <li>else <code>total salary = salary</code>; </li>
  </ul>
  
  <p>Here is my table:</p>
  
  <p>Table name: <code>myemp</code> </p>
  
  <p>Columns:</p>
  
  <pre><code>empno [Primary key], name, salary, commission, deptno
  
  create table myemp
  ( 
       empno number primary key,
       name varchar2(20),
       salary number,
       commission number,
       deptno number
  );
  </code></pre>
  
  <p>Query:</p>
  
  <pre><code>select
      name, salary, commission,
      (salary + ((salary*commission) / 100)) as "total_salary" 
  from myemp;
  </code></pre>
  
  <p>This query give incorrect result.</p>
  
  <p>When commission is <code>NULL</code>, then <code>total_salary = 0</code>. But it should be <code>total_salay=salary</code>;</p>
  
  <p>How to fix this?</p>