title: How to join in a WMI Query (WQL)
body: <p>I want to get the serial number of the boot-harddisk via a WQL query.</p>
  
  <p>The boot-partition can be retrieved using the following query:</p>
  
  <pre><code>SELECT * FROM Win32_DiskPartition where BootPartition=True
  </code></pre>
  
  <p>The serial number is in Win32_DiskDrive:</p>
  
  <pre><code>SELECT DeviceID, SerialNumber FROM Win32_DiskDrive
  </code></pre>
  
  <p><code>Win32_DiskDriveToDiskPartition</code> has the mapping of <code>Win32_DiskDrive</code> to <code>Win32_DiskPartition</code>.
  They are mapped <code>Win32_DiskDrive.DeviceID</code> to <code>Win32_DiskPartition.DeviceID</code> in <code>Win32_DiskDriveToDiskPartition</code></p>
  
  <p>How can I build a WQL query that inner joins <code>Win32_DiskPartition</code> and <code>Win32_DiskDrive</code>?
  Do I have to use Associators or does it work with INNER JOIN?</p>