CREATE TABLE member (member_id TEXT, name TEXT, nationality TEXT, role TEXT)
CREATE TABLE performance (performance_id DECIMAL, date TEXT, host TEXT, location TEXT, attendance DECIMAL)
CREATE TABLE member_attendance (member_id DECIMAL, performance_id DECIMAL, num_of_pieces DECIMAL)

Show the dates of performances with attending members whose roles are 'Violin'.
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"
SELECT "T3"."date" FROM "member_attendance" AS "T1" JOIN "member" AS "T2" ON "T1"."member_id" = "T2"."member_id" AND "T2"."role" = "Violin" JOIN "performance" AS "T3" ON "T1"."performance_id" = "T3"."performance_id"