title: Regarding Data functions in SQL
body: <p><strong>There's no start date for some of the rows in the start date</strong></p>
  <p>I have the below table, How to get the average of the difference between the start date and end date grouped by location in SQL</p>
  <p><a href="https://i.stack.imgur.com/j54FB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/j54FB.png" alt="Table: Loc" /></a></p>