Who are the attending members whose roles are "Viola"?
select name from member where role = "Viola"
How about Violin?
select name from member where role = "Violin"
Show me the dates of performances in which members in the result attended.
select t3.date from member_attendance as t1 join member as t2 on t1.member_id = t2.member_id join performance as t3 on t1.performance_id = t3.performance_id where t2.role = "Violin"