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"].
Problem Statement
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:
Departmenttable:
| 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).
Solution
1SELECT id,
2 SUM( IF (month = 'Jan', revenue, null) ) AS Jan_Revenue,
3 SUM( IF (month = 'Feb', revenue, null) ) AS Feb_Revenue,
4 SUM( IF (month = 'Mar', revenue, null) ) AS Mar_Revenue,
5 SUM( IF (month = 'Apr', revenue, null) ) AS Apr_Revenue,
6 SUM( IF (month = 'May', revenue, null) ) AS May_Revenue,
7 SUM( IF (month = 'Jun', revenue, null) ) AS Jun_Revenue,
8 SUM( IF (month = 'Jul', revenue, null) ) AS Jul_Revenue,
9 SUM( IF (month = 'Aug', revenue, null) ) AS Aug_Revenue,
10 SUM( IF (month = 'Sep', revenue, null) ) AS Sep_Revenue,
11 SUM( IF (month = 'Oct', revenue, null) ) AS Oct_Revenue,
12 SUM( IF (month = 'Nov', revenue, null) ) AS Nov_Revenue,
13 SUM( IF (month = 'Dec', revenue, null) ) AS Dec_Revenue
14 FROM Department
15 GROUP By id;
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