Find the name of the source user with the highest average trust score.
create table useracct (name varchar, u_id varchar, PRIMARY KEY (name)); create table trust (source_u_id varchar, PRIMARY KEY (source_u_id))
select t1.name from useracct as t1 join trust as t2 on t1.u_id = t2.source_u_id group by t2.source_u_id order by avg(trust) desc limit 1