返回各部门工资排名前三位的员工

CREATE OR REPLACE VIEW v AS
SELECT '20' AS depno, '101' AS empno, '3000' AS sal FROM DUAL
UNION ALL
SELECT '20' AS depno, '102' AS empno, '3000' AS sal FROM DUAL
UNION ALL
SELECT '20' AS depno, '103' AS empno, '2500' AS sal FROM DUAL
UNION ALL
SELECT '20' AS depno, '104' AS empno, '2000' AS sal FROM DUAL
UNION ALL
SELECT '20' AS depno, '105' AS empno, '1500' AS sal FROM DUAL
UNION ALL
SELECT '30' AS depno, '106' AS empno, '3000' AS sal FROM DUAL
UNION ALL
SELECT '30' AS depno, '107' AS empno, '2500' AS sal FROM DUAL
UNION ALL
SELECT '30' AS depno, '108' AS empno, '2000' AS sal FROM DUAL;
SELECT * FROM v;
CREATE OR REPLACE VIEW v AS
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