전체 평균

Coddy SQL 여정의 기초 섹션에 포함된 레슨. 72개 중 56번째.

챌린지

쉬움

사용 가능한 테이블 및 열:
enom_gilpane: part_id, rpm, watt, size
castle_loctus: part_id, rpm, watt, size
honpan_bilopsa: part_id, rpm, watt, size
yurnol_qoltam: part_id, rpm, watt, size

마지막으로 각 part_id에 대한 평균 품질을 계산하세요.

part_id와 avg_quality를 반환하고, avg_quality를 기준으로 내림차순 정렬하세요.

직접 해보기

-- 이 네 개의 제품 블록과 결합 블록은 지난 수업에서 이어져 온 것입니다
WITH filtered_enom_gilpane_quality as (
    WITH enom_gilpane_quality as (
        SELECT part_id, ((rpm * watt) / size) as quality
        FROM (
            SELECT part_id, rpm, watt + (select avg(watt) from enom_gilpane) as watt, size
            FROM enom_gilpane
        )
    )

    SELECT *
    FROM enom_gilpane_quality
    WHERE quality > (select avg(quality) from enom_gilpane_quality)
),
filtered_castle_loctus_quality as (
    WITH castle_loctus_quality as (
        SELECT part_id, ((rpm * watt) / size) as quality
        FROM (
            SELECT part_id, rpm, watt + (select avg(watt) from castle_loctus) as watt, size
            FROM castle_loctus
        )
    )

    SELECT *
    FROM castle_loctus_quality
    WHERE quality > (select avg(quality) from castle_loctus_quality)
),
filtered_honpan_bilopsa_quality as (
    WITH honpan_bilopsa_quality as (
        SELECT part_id, ((rpm * watt) / size) as quality
        FROM (
            SELECT part_id, rpm, watt + (select avg(watt) from honpan_bilopsa) as watt, size
            FROM honpan_bilopsa
        )
    )

    SELECT *
    FROM honpan_bilopsa_quality
    WHERE quality > (select avg(quality) from honpan_bilopsa_quality)
),
filtered_yurnol_qoltam_quality as (
    WITH yurnol_qoltam_quality as (
        SELECT part_id, ((rpm * watt) / size) as quality
        FROM (
            SELECT part_id, rpm, watt + (select avg(watt) from yurnol_qoltam) as watt, size
            FROM yurnol_qoltam
        )
    )

    SELECT *
    FROM yurnol_qoltam_quality
    WHERE quality > (select avg(quality) from yurnol_qoltam_quality)
),
quality_table as (
    SELECT * FROM filtered_enom_gilpane_quality
    UNION ALL
    SELECT * FROM filtered_castle_loctus_quality
    UNION ALL
    SELECT * FROM filtered_honpan_bilopsa_quality
    UNION ALL
    SELECT * FROM filtered_yurnol_qoltam_quality
)

-- 결합된 행을 제품 부품당 하나의 행으로 줄이되, 가장 큰 평균이 먼저 오도록 합니다
SELECT part_id, ____ as avg_quality
FROM quality_table
GROUP BY ____
ORDER BY ____