CREATE TABLE repair_assignment (technician_id NUMBER, repair_id NUMBER, machine_id NUMBER)
CREATE TABLE machine (machine_id NUMBER, making_year NUMBER, class CLOB, team CLOB, machine_series CLOB, value_points NUMBER, quality_rank NUMBER)
CREATE TABLE repair (repair_id NUMBER, name CLOB, launch_date CLOB, notes CLOB)
CREATE TABLE technician (technician_id NUMBER, name CLOB, team CLOB, starting_year NUMBER, age NUMBER)

Show the starting years shared by technicians from team 'CLE' and 'CWS'.
SELECT starting_year FROM technician WHERE team = "CLE" INTERSECT SELECT starting_year FROM technician WHERE team = "CWS"
SELECT "starting_year" FROM "technician" WHERE "CLE" = "team" INTERSECT SELECT "starting_year" FROM "technician" WHERE "CWS" = "team"