MySQL ROW_NUMBER, RANK, DENSE_RANK 의 차이점

[주인장]

ROW_NUMBER, RANK, DENSE_RANK 의 차이점

• ROW_NUMBER(): 순위를 건너뛰지 않고 부여 (고유 번호).
• RANK(): 순위를 매기지만, 동일 값은 같은 순위로 처리하고 다음 순위를 건너뜀.
• DENSE_RANK(): 동일 값은 같은 순위로 처리하되, 순위가 연속적으로 부여됨.

SELECT

    emp_no,

    department,

    salary,

    ROW_NUMBER() OVER(PARTITION BY department ORDER BY SALARY DESC) as dept_row_number,

    RANK() OVER(PARTITION BY department ORDER BY SALARY DESC) as dept_salary_rank,

    RANK() OVER(ORDER BY salary DESC) as overall_rank,

    DENSE_RANK() OVER(ORDER BY salary DESC) as overall_dense_rank,

    ROW_NUMBER() OVER(ORDER BY salary DESC) as overall_num

FROM employees ORDER BY overall_rank;