title: Track Deletion with combined index Azure Cognitive Search
body: <p>I have a combined index that crawls data from Azure SQL and Blob and are mapped based a common column.</p>
  <p>The mapped blob document is optional.</p>
  <p>When there is no blob document the search indexer indexes the respective SQL row setting the content propertyas null and if the document is available the content property shows correct data.</p>
  <p>I have enabled BLOB deletion tracking and the issue comes when a blob document is deleted. The deletion policy triggers and also removes the mapped SQL row values from index.</p>
  <p>I was expecting that the content property will be set to null, but the deletion policy also removes the mapped SQL row values from index.</p>
  <p>What am I doing wrong? Kindly help.</p>
  <p>Thanks a lot in advance..</p>
  <p>BR</p>