추가 순위 함수

Snowflake의 Window 함수

Jake Roach

Field Data Engineer

RANK vs. DENSE_RANK

SELECT
    workout_duration,

    RANK() OVER(
        ORDER BY workout_duration DESC
    ) AS r,


    -- Without gaps!
    DENSE_RANK() OVER(
        ORDER BY workout_duration DESC
    ) AS dr


FROM FITNESS.workouts;

   workout_duration  |   r   |   dr
  ------------------ | ----- | -----
         78          |   1   |   1
         71          |   2   |   2
         71          |   2   |   2

    ***  68          |   4   |   3  ***

         67          |   5   |   4
         67          |   5   |   4
         67          |   5   |   4
         63          |   8   |   5
         61          |   9   |   6

NTH_VALUE

SELECT
    <field>,
    <another-field>,


    NTH_VALUE(<1>, <n>) OVER(

        PARTITION BY <2>
        ORDER BY <3>

    ) AS <alias>


FROM <SCHEMA>.<table>;

NTH_VALUE는 윈도우에서 n번째 행의 지정 값을 반환합니다. FIRST/LAST_VALUE와 유사합니다.

<1>: 가져올 값

<n>: 가져올 행 번호

<2>: 선택적 파티션 기준 필드

<3>: ORDER BY가 레코드 순위를 결정

NTH_VALUE

SELECT
    gym_location,
    workout_duration,


    -- 각 지점별 두 번째로 긴 운동 시간 반환
    NTH_VALUE(workout_duration, 2) OVER(

        PARTITION BY gym_location
        ORDER BY workout_duration DESC

    ) AS second_longest_workout


FROM FITNESS.workouts;

NTH_VALUE

      gym_location   |  workout_duration  |  second_longest_workout 
     --------------- | ------------------ | ------------------------
        New York     |        71          |           68            
        New York     |        68          |           68
        New York     |        67          |           68

        Los Angeles  |        78          |           67
        Los Angeles  |        67          |           67
        Los Angeles  |        67          |           67
        Los Angeles  |        63          |           67

        Miami        |        71          |           61
        Miami        |        61          |           61

종합 적용

SELECT
    gym_location, workout_duration,

    NTH_VALUE(workout_duration, 2) OVER(
        PARTITION BY gym_location
        ORDER BY workout_duration DESC
    ) AS second_longest_workout,

    RANK() OVER(PARTITION BY gym_location ORDER BY workout_duration DESC) AS r,

    DENSE_RANK() OVER(PARTITION BY gym_location ORDER BY workout_duration DESC) AS dr,

FROM FITNESS.workouts;

종합 적용

      gym_location   |  workout_duration  |  second_longest_workout  |  r  |   dr  
     --------------- | ------------------ | ------------------------ | --- | -----
        New York     |        71          |           68             |  1  |   1
        New York     |        68          |           68             |  2  |   2
        New York     |        67          |           68             |  3  |   3

        Los Angeles  |        78          |           67             |  1  |   1
        Los Angeles  |        67          |           67             |  2  |   2
        Los Angeles  |        67          |           67             |  2  |   2
        Los Angeles  |        63          |           67             |  4  |   3

        Miami        |        71          |           61             |  1  |   1
        Miami        |        61          |           61             |  2  |   2

Vamos praticar!

Snowflake의 Window 함수