Q&A for user experience researchers and experts
with posts_2010 as ( select distinct owneruserid from posts where year(creationdate) = 2010 ), posts_2015 as ( select distinct owneruserid from posts where year(creationdate) = 2015 ) select distinct top 10 u.displayname from users u join posts_2015 p15 on u.id = p15.owneruserid left join posts_2010 p10 on u.id = p10.owneruserid where p10.owneruserid is null order by u.displayname;