title: DATEDIFF on Dates in Multiple Rows
body: <p>I'm trying to find the number of days between the initial visit and the return visit for customers in a restaurant, but I'm having some trouble doing so since the dates of the initial visit and the return visit are on separate rows. The data is sensitive, so I can't post it here, but it looks something like this:</p>
  
  <p><img src="https://i.stack.imgur.com/sOlfE.jpg" alt="Picture of Data"></p>
  
  <p>If DATEDIFF isn't the best choice here, can someone suggest another function?</p>