LeetCode:197. Rising Temperature

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题目描述

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

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+---------+------------------+------------------+
| Id(INT) | RecordDate(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:

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

考查date_sub的用法，date_sub(date, interval k day)为找到date的前k天并返回。

date可用curdate()表示今天。

代码实现

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select s.id from weather as s, weather as t
where s.temperature > t.temperature and t.recorddate = date_sub(s.recorddate, interval 1 day);