197. Rising Temperature

id is the column with unique values for this table.
There are no different rows with the same recordDate.
This table contains information about the temperature on a certain day.

Write a solution to find all dates' Id with higher temperatures compared to its previous dates (yesterday).

Return the result table in any order.

The result format is in the following example.

Input:
Weather table:

Output:

Explanation:
In 2015-01-02, the temperature was higher than the previous day (10 -> 25).
In 2015-01-04, the temperature was higher than the previous day (20 -> 30).

解答：

SELECT w1.id FROM Weather w1, Weather w2 
WHERE DATEDIFF(w1.recordDate,w2.recordDate) = 1 
AND w1.temperature > w2.temperature

學習點：
1.自己跟自己比較時SELECT自己兩次。
2.DATEDIFF ( datepart , startdate , enddate ) datepart不傳時返回兩個日期之間的差異。