当前位置：首页 > article >正文

leetcode----mysql

article 2024/12/22 13:54:14

1179. 重新格式化部门表 - 力扣（LeetCode）

表 Department：

+---------------+---------+
| Column Name   | Type    |
+---------------+---------+
| id            | int     |
| revenue       | int     |
| month         | varchar |
+---------------+---------+
在 SQL 中，(id, month) 是表的联合主键。
这个表格有关于每个部门每月收入的信息。
月份（month）可以取下列值 ["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"]。

重新格式化表格，使得 每个月 都有一个部门 id 列和一个收入列。

以 任意顺序 返回结果表。

结果格式如以下示例所示。

示例 1：

输入：
Department table:
+------+---------+-------+
| id   | revenue | month |
+------+---------+-------+
| 1    | 8000    | Jan   |
| 2    | 9000    | Jan   |
| 3    | 10000   | Feb   |
| 1    | 7000    | Feb   |
| 1    | 6000    | Mar   |
+------+---------+-------+
输出：
+------+-------------+-------------+-------------+-----+-------------+
| id   | Jan_Revenue | Feb_Revenue | Mar_Revenue | ... | Dec_Revenue |
+------+-------------+-------------+-------------+-----+-------------+
| 1    | 8000        | 7000        | 6000        | ... | null        |
| 2    | 9000        | null        | null        | ... | null        |
| 3    | null        | 10000       | null        | ... | null        |
+------+-------------+-------------+-------------+-----+-------------+
解释：四月到十二月的收入为空。 
请注意，结果表共有 13 列（1 列用于部门 ID，其余 12 列用于各个月份）。

SELECT id,

SUM(CASE WHEN month='Jan' THEN revenue END) AS Jan_Revenue,

SUM(CASE WHEN month='Feb' THEN revenue END) AS Feb_Revenue,

SUM(CASE WHEN month='Mar' THEN revenue END) AS Mar_Revenue,

SUM(CASE WHEN month='Apr' THEN revenue END) AS Apr_Revenue,

SUM(CASE WHEN month='May' THEN revenue END) AS May_Revenue,

SUM(CASE WHEN month='Jun' THEN revenue END) AS Jun_Revenue,

SUM(CASE WHEN month='Jul' THEN revenue END) AS Jul_Revenue,

SUM(CASE WHEN month='Aug' THEN revenue END) AS Aug_Revenue,

SUM(CASE WHEN month='Sep' THEN revenue END) AS Sep_Revenue,

SUM(CASE WHEN month='Oct' THEN revenue END) AS Oct_Revenue,

SUM(CASE WHEN month='Nov' THEN revenue END) AS Nov_Revenue,

SUM(CASE WHEN month='Dec' THEN revenue END) AS Dec_Revenue

FROM department

GROUP BY id