【leetcode Database】197. Rising Temperature

題目：

Given a Weather table, write a SQL query to find all dates' Ids with higher temperature compared to its previous (yesterday's) dates.

+---------+------------+------------------+
| Id(INT) | Date(DATE) | Temperature(INT) |
+---------+------------+------------------+
|       1 | 2015-01-01 |               10 |
|       2 | 2015-01-02 |               25 |
|       3 | 2015-01-03 |               20 |
|       4 | 2015-01-04 |               30 |
+---------+------------+------------------+

For example, return the following Ids for the above Weather table:

+----+
| Id |
+----+
|  2 |
|  4 |
+----+

解析：

本題可以用自連接來做，用表的別名來解決即可。代碼如下：

# Write your MySQL query statement below
SELECT a.Id  FROM Weather a,Weather b WHERE a.Temperature > b.Temperature AND a.Date = ADDDATE(b.Date,1);