title: SharePoint 2010: efficient union query across site collections?
body: <p>In SharePoint 2010, I would like to create a list in one <code>SiteCollection</code> that queries data from several other <code>SiteCollections</code> that have common fields:</p>
  
  <p><img src="https://i.stack.imgur.com/qnlVk.png" alt="alt text"></p>
  
  <p>Is this possible, and if so - can it be done efficiently?</p>
  
  <p>The current proposed solutions involves setting up <code>EventReceivers</code> on each of the <code>SiteCollections</code> that we want to query, and updating a master list (the <code>OverviewSiteCollection</code>) with the new data each time one of the SiteCollections is updated or has data added.</p>
  
  <p>Is there a better way to achieve what we want to achieve??</p>