Question

1179. Reformat Department Table

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Description

Table: Department

+-------------+---------+
| Column Name | Type  |
+-------------+---------+
| id      | int   |
| revenue   | int   |
| month     | varchar |
+-------------+---------+
In SQL,(id, month) is the primary key of this table.
The table has information about the revenue of each department per month.
The month has values in ["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"].

 

Reformat the table such that there is a department id column and a revenue column for each month.

Return the result table in any order.

The result format is in the following example.

 

Example 1:

Input: 
Department table:
+------+---------+-------+
| id   | revenue | month |
+------+---------+-------+
| 1  | 8000  | Jan   |
| 2  | 9000  | Jan   |
| 3  | 10000   | Feb   |
| 1  | 7000  | Feb   |
| 1  | 6000  | Mar   |
+------+---------+-------+
Output: 
+------+-------------+-------------+-------------+-----+-------------+
| id   | Jan_Revenue | Feb_Revenue | Mar_Revenue | ... | Dec_Revenue |
+------+-------------+-------------+-------------+-----+-------------+
| 1  | 8000    | 7000    | 6000    | ... | null    |
| 2  | 9000    | null    | null    | ... | null    |
| 3  | null    | 10000     | null    | ... | null    |
+------+-------------+-------------+-------------+-----+-------------+
Explanation: The revenue from Apr to Dec is null.
Note that the result table has 13 columns (1 for the department id + 12 for the months).

Solutions

Solution 1

# Write your MySQL query statement below
SELECT
  id,
  SUM(
    CASE month
      WHEN 'Jan' THEN revenue
    END
  ) AS Jan_Revenue,
  SUM(
    CASE month
      WHEN 'Feb' THEN revenue
    END
  ) AS Feb_Revenue,
  SUM(
    CASE month
      WHEN 'Mar' THEN revenue
    END
  ) AS Mar_Revenue,
  SUM(
    CASE month
      WHEN 'Apr' THEN revenue
    END
  ) AS Apr_Revenue,
  SUM(
    CASE month
      WHEN 'May' THEN revenue
    END
  ) AS May_Revenue,
  SUM(
    CASE month
      WHEN 'Jun' THEN revenue
    END
  ) AS Jun_Revenue,
  SUM(
    CASE month
      WHEN 'Jul' THEN revenue
    END
  ) AS Jul_Revenue,
  SUM(
    CASE month
      WHEN 'Aug' THEN revenue
    END
  ) AS Aug_Revenue,
  SUM(
    CASE month
      WHEN 'Sep' THEN revenue
    END
  ) AS Sep_Revenue,
  SUM(
    CASE month
      WHEN 'Oct' THEN revenue
    END
  ) AS Oct_Revenue,
  SUM(
    CASE month
      WHEN 'Nov' THEN revenue
    END
  ) AS Nov_Revenue,
  SUM(
    CASE month
      WHEN 'Dec' THEN revenue
    END
  ) AS Dec_Revenue
FROM Department
GROUP BY 1;