197. Rising Temperature (Easy)

Posted 2020-09-19 sixu

Source:  https://leetcode.com/problems/rising-temperature/#/description
Description:

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 |
+----+

 

Solution:

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