問題描述：

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 |
+----+

找出溫度比昨天高的那一天對應的ID。

問題求解：

1、where

select w1.Id from Weather w1, Weather w2 
where TO_DAYS(w1.Date)=TO_DAYS(w2.Date)+1 and w1.Temperature>w2.Temperature;

2、inner join … on

select w1.Id from
 
 Weather w1 inner join Weather w2 
on TO_DAYS(w1.Date)=TO_DAYS(w2.Date)+1 and w1.Temperature>w2.Temperature;