title: How can I replace NULL category titles in MySQL ROLLUP function?
body: <p>Using the MySQL query below, I have created a pivot table which is pretty much exactly what I am looking for. I would however like to replace the NULL values with actual descriptions, such as SubTotal and GrandTotal. Here is the pivot table format as displayed on my PHP output (hopefully the formatting is somewhat legible!).</p>
  
  <pre><code>Name    Division 1  Division 2  Division 3  Division 4  Location
  Name 1
  Name 2
  Name 3
  NULL    Total       Total       Total       Total
  Name 4
  Name 5
  NULL    Total       etc
  NULL    Column Grand Total 
  </code></pre>
  
  <p>Here is the query I used to generate the table. After researching this issue, it seems like the CASE function is the way to go. However, when I add the two CASE lines into the query below, it doesn't seem to want to work. The mysql_error that returns says that the "GROUPING function does not exist". </p>
  
  <pre><code>SELECT 
  CASE WHEN (GROUPING(name)=1) THEN 'MainTotal' ELSE name END AS name, 
  CASE WHEN (GROUPING(location)=1) THEN 'SubTotal' ELSE location END AS location, 
  name AS Name,
  SUM(IF(division='OEM',totalHours,NULL)) AS OEM,
  SUM(IF(division='A/M',totalHours,NULL)) AS AM,
  SUM(IF(division='SKF',totalHours,NULL)) AS SKF,
  SUM(IF(division='RE',totalHours,NULL)) AS RE,
  location as Location
  FROM $databasetable GROUP BY location, name 
  WITH ROLLUP
  </code></pre>
  
  <p>Can anybody tell me what I'm doing wrong? Is the CASE function the way to go to replace the NULL category titles?</p>
  
  <p>Thanks in advance!</p>