Question:
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 | +----+
Analysis：
给出一张温度表格，写一个SQL语句找出所有的温度比前一天温度高的日期id。
数据库的题目，常年不用都忘了。跑去官网查文档，一点点拾起来吧~
Answer：
select w1.id from Weather w1, Weather w2 where w1.Temperature > w2.Temperature and DATEDIFF(w1.Date, w2.Date) = 1;