需要查询以显示同时拥有男性和女性员工的部门

CREATE TABLE departments(deptname VARCHAr2(20),sex VARCHAR2(2));

INSERT INTO departments VALUES('SALES','M');
INSERT INTO departments VALUES('SALES','F');
INSERT INTO departments VALUES('SALES','M');
INSERT INTO departments VALUES('SALES','F');
INSERT INTO departments VALUES('ENG','M');
INSERT INTO departments VALUES('ENG','F');
INSERT INTO departments VALUES('MKT','M');
INSERT INTO departments VALUES('CLE','F');
INSERT INTO departments VALUES('AUTO','M');
INSERT INTO departments VALUES('AUTO','M');
INSERT INTO departments VALUES('ENV','F');
INSERT INTO departments VALUES('ENV','F');

Expected Output
Deptname   Sex
SALES      M
SALES      F
SALES      M
SALES      F
ENG        M
ENG        F

请帮帮我。
先谢了。