title: Mysql, get the most recent values of each 2 columns pair
body: <p>Here is a simple table</p>
  
  <p><a href="https://i.stack.imgur.com/5AYfY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5AYfY.png" alt="table"></a></p>
  
  <p>I would like to return only the most recent by creation_date) unique pair of item_key and category_key</p>
  
  <p>In this case request should return the line 1,3,4.
  1, 3 because it's an unique pair and 4 because the line are most recent pair of ["titi" and 3] then the line 3</p>
  
  <p>here my expected result :</p>
  
  <p><a href="https://i.stack.imgur.com/40pYt.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/40pYt.png" alt="result"></a></p>
  
  <p>I use mysql 5.7 database.</p>
  
  <p>Thanks for your help</p>