add 1179

Author: fishercoder1534

README.md

@@ -813,6 +813,7 @@ Your ideas/fixes/algorithms are more than welcome!
 
 |  #  |      Title     |   Solutions   | Time          | Space         | Difficulty  | Tag          
 |-----|----------------|---------------|---------------|---------------|-------------|--------------
+|1179|[Reformat Department Table](https://leetcode.com/problems/reformat-department-table/)|[Solution](../master/database/_1179.sql) | | | Easy |
 |1069|[Product Sales Analysis II](https://leetcode.com/problems/product-sales-analysis-ii/)|[Solution](../master/database/_1069.sql) | | | Easy |
 |1068|[Product Sales Analysis I](https://leetcode.com/problems/product-sales-analysis-i/)|[Solution](../master/database/_1068.sql) | | | Easy |
 |627|[Swap Salary](https://leetcode.com/problems/swap-salary/)|[Solution](../master/database/_627.sql) | | | Easy |

database/_1179.sql

@@ -0,0 +1,61 @@
+--1179. Reformat Department Table
+--
+--SQL Schema
+--Table: Department
+--
+--+---------------+---------+
+--| Column Name   | Type    |
+--+---------------+---------+
+--| id            | int     |
+--| revenue       | int     |
+--| month         | varchar |
+--+---------------+---------+
+--(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"].
+--
+--Write an SQL query to reformat the table such that there is a department id column and a revenue column for each month.
+--
+--The query result format is in the following example:
+--
+--Department table:
+--+------+---------+-------+
+--| id   | revenue | month |
+--+------+---------+-------+
+--| 1    | 8000    | Jan   |
+--| 2    | 9000    | Jan   |
+--| 3    | 10000   | Feb   |
+--| 1    | 7000    | Feb   |
+--| 1    | 6000    | Mar   |
+--+------+---------+-------+
+--
+--Result table:
+--+------+-------------+-------------+-------------+-----+-------------+
+--| id   | Jan_Revenue | Feb_Revenue | Mar_Revenue | ... | Dec_Revenue |
+--+------+-------------+-------------+-------------+-----+-------------+
+--| 1    | 8000        | 7000        | 6000        | ... | null        |
+--| 2    | 9000        | null        | null        | ... | null        |
+--| 3    | null        | 10000       | null        | ... | null        |
+--+------+-------------+-------------+-------------+-----+-------------+
+--
+--Note that the result table has 13 columns (1 for the department id + 12 for the months).
+
+
+-- Write your MySQL query statement below
+
+--group by solution
+select id,
+max(case when month = 'Jan' then revenue else null end) as 'Jan_Revenue',
+max(case when month = 'Feb' then revenue else null end) as 'Feb_Revenue',
+max(case when month = 'Mar' then revenue else null end) as 'Mar_Revenue',
+max(case when month = 'Apr' then revenue else null end) as 'Apr_Revenue',
+max(case when month = 'May' then revenue else null end) as 'May_Revenue',
+max(case when month = 'Jun' then revenue else null end) as 'Jun_Revenue',
+max(case when month = 'Jul' then revenue else null end) as 'Jul_Revenue',
+max(case when month = 'Aug' then revenue else null end) as 'Aug_Revenue',
+max(case when month = 'Sep' then revenue else null end) as 'Sep_Revenue',
+max(case when month = 'Oct' then revenue else null end) as 'Oct_Revenue',
+max(case when month = 'Nov' then revenue else null end) as 'Nov_Revenue',
+max(case when month = 'Dec' then revenue else null end) as 'Dec_Revenue'
+from Department
+group by id