Menu
Coddy logo textTech

Общее среднее значение

Часть раздела Основы путешествия по SQL на Coddy. Урок 56 из 72.

challenge icon

Задание

Легко

Доступные таблицы и столбцы:

  • <strong>enom_gilpane</strong>: <strong>part_id</strong>, <strong>rpm</strong>, <strong>watt</strong>, <strong>size</strong>
  • <strong>castle_loctus</strong>: <strong>part_id</strong>, <strong>rpm</strong>, <strong>watt</strong>, <strong>size</strong>
  • <strong>honpan_bilopsa</strong>: <strong>part_id</strong>, <strong>rpm</strong>, <strong>watt</strong>, <strong>size</strong>
  • <strong>yurnol_qoltam</strong>: <strong>part_id</strong>, <strong>rpm</strong>, <strong>watt</strong>, <strong>size</strong>

 

Наконец, рассчитайте среднее качество для каждого part_id.

Верните part_id, avg_quality, отсортированные по avg_quality в порядке убывания.

Попробуйте сами

-- Эти четыре блока продуктов и объединённый блок перенесены из предыдущего урока
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
)

-- Сведите объединённые строки к одной строке на каждую деталь продукта, сначала наибольшее среднее
SELECT part_id, ____ as avg_quality
FROM quality_table
GROUP BY ____
ORDER BY ____

Все уроки раздела Основы

Потренируйтесь самостоятельно: Песочница SQL