How to select from 3 tables while using count on 1, and sum on another?
I assume you have multiple entries in shows, views table for each user. When joining all three together, you get more rows than you expect: if for some user you have x rows in table shows and y rows in table views, then the result set contains x*y rows for that user, so you sum each entry in shows y times, and each entry in views table gets counted x times.

You need to aggregate each table separately, and then join the results:

select t1.sum1, t2.cnt, u.user_name
from users u
left join (select show_user, sum(show_count) sum1 from shows group by show_user) t1 on u.user = t1.show_user
left join (select view_user, count(view_views) cnt from views group by view_user) t2 on u.user = t2.view_user


SQLFiddle