1082-SalesAnalysisI.sql

-- 1082. Sales Analysis I
-- Table: Product
--
-- +--------------+---------+
-- | Column Name  | Type    |
-- +--------------+---------+
-- | product_id   | int     |
-- | product_name | varchar |
-- | unit_price   | int     |
-- +--------------+---------+
-- product_id is the primary key of this table.
-- Each row of this table indicates the name and the price of each product.
-- Table: Sales
--
-- +-------------+---------+
-- | Column Name | Type    |
-- +-------------+---------+
-- | seller_id   | int     |
-- | product_id  | int     |
-- | buyer_id    | int     |
-- | sale_date   | date    |
-- | quantity    | int     |
-- | price       | int     |
-- +-------------+---------+
-- This table has no primary key, it can have repeated rows.
-- product_id is a foreign key to the Product table.
-- Each row of this table contains some information about one sale.
--  
--
-- Write an SQL query that reports the best seller by total sales price, If there is a tie, report them all.
--
-- Return the result table in any order.
--
-- The query result format is in the following example.
--
--  
--
-- Example 1:
--
-- Input:
-- Product table:
-- +------------+--------------+------------+
-- | product_id | product_name | unit_price |
-- +------------+--------------+------------+
-- | 1          | S8           | 1000       |
-- | 2          | G4           | 800        |
-- | 3          | iPhone       | 1400       |
-- +------------+--------------+------------+
-- Sales table:
-- +-----------+------------+----------+------------+----------+-------+
-- | seller_id | product_id | buyer_id | sale_date  | quantity | price |
-- +-----------+------------+----------+------------+----------+-------+
-- | 1         | 1          | 1        | 2019-01-21 | 2        | 2000  |
-- | 1         | 2          | 2        | 2019-02-17 | 1        | 800   |
-- | 2         | 2          | 3        | 2019-06-02 | 1        | 800   |
-- | 3         | 3          | 4        | 2019-05-13 | 2        | 2800  |
-- +-----------+------------+----------+------------+----------+-------+
-- Output:
-- +-------------+
-- | seller_id   |
-- +-------------+
-- | 1           |
-- | 3           |
-- +-------------+
-- Explanation: Both sellers with id 1 and 3 sold products with the most total price of 2800.
--

-- Write your MySQL query statement below
SELECT
    seller_id
FROM
    ( -- 销售 & 总额
        SELECT
            seller_id,
            SUM(price) AS total
        FROM
            Sales
        GROUP BY
            seller_id
    ) AS a
WHERE
    total = (
        SELECT -- 取最大的值
            MAX(b.total)
        FROM
        ( -- 销售 & 总额
            SELECT
                seller_id,
                SUM(price) AS total
            FROM
                Sales
            GROUP BY
                seller_id
        ) AS b
    )