CREATE TABLE member_attendance (Member_ID VARCHAR2, Performance_ID VARCHAR2)
CREATE TABLE performance (Date VARCHAR2, Performance_ID VARCHAR2)
CREATE TABLE member (Member_ID VARCHAR2, Role VARCHAR2)

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" "T1" JOIN "member" "T2" ON "T1"."Member_ID" = "T2"."Member_ID" AND "T2"."Role" = "Violin" JOIN "performance" "T3" ON "T1"."Performance_ID" = "T3"."Performance_ID"