1393.(Medium)股票的资本损益

Stocks 表：

+---------------+---------+
| Column Name   | Type    |
+---------------+---------+
| stock_name    | varchar |
| operation     | enum    |
| operation_day | int     |
| price         | int     |
+---------------+---------+
(stock_name, day) 是这张表的主键
operation 列使用的是一种枚举类型，包括：('Sell','Buy')
此表的每一行代表了名为 stock_name 的某支股票在 operation_day 这一天的操作价格。
保证股票的每次'Sell'操作前，都有相应的'Buy'操作。

编写一个SQL查询来报告每支股票的资本损益。

股票的资本损益是一次或多次买卖股票后的全部收益或损失。

以任意顺序返回结果即可。

SQL查询结果的格式如下例所示：

Stocks 表:
+---------------+-----------+---------------+--------+
| stock_name    | operation | operation_day | price  |
+---------------+-----------+---------------+--------+
| Leetcode      | Buy       | 1             | 1000   |
| Corona Masks  | Buy       | 2             | 10     |
| Leetcode      | Sell      | 5             | 9000   |
| Handbags      | Buy       | 17            | 30000  |
| Corona Masks  | Sell      | 3             | 1010   |
| Corona Masks  | Buy       | 4             | 1000   |
| Corona Masks  | Sell      | 5             | 500    |
| Corona Masks  | Buy       | 6             | 1000   |
| Handbags      | Sell      | 29            | 7000   |
| Corona Masks  | Sell      | 10            | 10000  |
+---------------+-----------+---------------+--------+

Result 表:
+---------------+-------------------+
| stock_name    | capital_gain_loss |
+---------------+-------------------+
| Corona Masks  | 9500              |
| Leetcode      | 8000              |
| Handbags      | -23000            |
+---------------+-------------------+
Leetcode 股票在第一天以1000美元的价格买入，在第五天以9000美元的价格卖出。资本收益=9000-1000=8000美元。
Handbags 股票在第17天以30000美元的价格买入，在第29天以7000美元的价格卖出。资本损失=7000-30000=-23000美元。
Corona Masks 股票在第1天以10美元的价格买入，在第3天以1010美元的价格卖出。在第4天以1000美元的价格再次购买，在第5天以500美元的价格出售。最后，它在第6天以1000美元的价格被买走，在第10天以10000美元的价格被卖掉。资本损益是每次（’Buy'->'Sell'）操作资本收益或损失的和=（1010-10）+（500-1000）+（10000-1000）=1000-500+9000=9500美元。

来源：力扣（LeetCode）

链接：https://leetcode-cn.com/problems/capital-gainloss

著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

Solution

SELECT stock_name, 
    SUM(IF(operation='Sell',price,-price)) capital_gain_loss
FROM Stocks 
GROUP BY stock_name;

Table Schema

Create Table If Not Exists Stocks (stock_name varchar(15), operation ENUM('Sell', 'Buy'), operation_day int, price int);
Truncate table Stocks;
insert into Stocks (stock_name, operation, operation_day, price) values ('Leetcode', 'Buy', '1', '1000');
insert into Stocks (stock_name, operation, operation_day, price) values ('Corona Masks', 'Buy', '2', '10');
insert into Stocks (stock_name, operation, operation_day, price) values ('Leetcode', 'Sell', '5', '9000');
insert into Stocks (stock_name, operation, operation_day, price) values ('Handbags', 'Buy', '17', '30000');
insert into Stocks (stock_name, operation, operation_day, price) values ('Corona Masks', 'Sell', '3', '1010');
insert into Stocks (stock_name, operation, operation_day, price) values ('Corona Masks', 'Buy', '4', '1000');
insert into Stocks (stock_name, operation, operation_day, price) values ('Corona Masks', 'Sell', '5', '500');
insert into Stocks (stock_name, operation, operation_day, price) values ('Corona Masks', 'Buy', '6', '1000');
insert into Stocks (stock_name, operation, operation_day, price) values ('Handbags', 'Sell', '29', '7000');
insert into Stocks (stock_name, operation, operation_day, price) values ('Corona Masks', 'Sell', '10', '10000');