title: How to simply check if a DateTime column is within 30 days of today?
body: <p>I have a column in my table called <code>DateTimeOfBid</code>, I need to fetch all entities where DateTimeOfBid is within 30 days of today.</p>
  
  <p>I'm using Entity-Framework 4 to access my data.</p>
  
  <p>Here's what I have so far:</p>
  
  <pre><code>EFUserAuctionLanceRepository userAuctionLanceRepository = new EFUserAuctionLanceRepository();
  
  var potentialDiscount = userAuctionLanceRepository.FindAllUserAuctionLances()
                                                    .Where(u =&gt; u.UserId == user.UserId &amp;&amp; u.AccountableForShopDiscount == true);
  
  var discount = potentialDiscount.Where(p =&gt; p.DateTimeOfLance is within 30 days of today?)
  </code></pre>
  
  <p>How can I write this small query?</p>