title: SUMIFS IN SQL QUERY
body: <p>I need to create size categories in my SQL query from DB2 database. </p>
  
  <p><a href="https://i.stack.imgur.com/i244q.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/i244q.png" alt="enter image description here"></a></p>
  
  <p>I was thinking about windowed function  but I do not know how to start. </p>
  
  <p>Any thoughts? </p>