title: Show Zero if there is no record count - ORACLE SQL query
body: <p>The below Oracle query gives if there are any different errors with <code>error_message</code> and <code>Serial_num</code>.  </p>
  
  <p>If there is ZERO or No <code>Different error</code> count instead of showing Blank/Null result.  How can i see the output like this?  I tried with <code>NVL(error_message,0)</code> and <code>COALESCE (Sum(total),0)</code> but not getting the desired output. </p>
  
  <p><strong>Expected output</strong>: </p>
  
  <pre><code>1   Different Errors:       0
  </code></pre>
  
  <p>Oracle SQL Query:</p>
  
  <pre class="lang-sql prettyprint-override"><code>SELECT 
    1 as Index_Num, 
    CONCAT('Different Errors:  ', error_message || '# ' || serial_num), 
    SUM(total) 
  FROM ( 
    SELECT error_message, serial_num, COUNT(*) total 
    FROM Table1 
    WHERE error_message NOT LIKE '%INVALID%' 
    GROUP BY error_message, serial_num
  ) 
  GROUP BY error_message, serial_num
  </code></pre>