SQL -4

Posted 2021-06-14 yuexiuping

7.上升的温度

需求：编写一个 SQL 查询，来查找与之前（昨天的）日期相比温度更高的所有日期的 Id。

结果展示：

Id
2
4

建表语句：

Create table If Not Exists Weather (Id int, RecordDate date, Temperature int);
Truncate table Weather;
insert into Weather (Id, RecordDate, Temperature) values (1, \'2015-01-01\', 10);
insert into Weather (Id, RecordDate, Temperature) values (2, \'2015-01-02\', 25);
insert into Weather (Id, RecordDate, Temperature) values (3, \'2015-01-03\', 20);
insert into 1Weather (Id, RecordDate, Temperature) values (4, \'2015-01-04\', 30);

方法1：

select 
	w.id as id,
from 
	Weather w1
join 
	Weather w2
on 
	datadiff(w1.RecordDate,w2.RecordDate) = 1
and w1.Temperature > w2.Temperature;

方法2：

select 
	id 
from 
	(select
    	id,
   		RecordDate，
    	Temperature，
    	lag(RecordDate,1,9999-99-99) over(order by RecordDate) yd,
    	lag(Temperature,1,999) over(order by RecordDate) yt
     from 
     	Weather
    ) tmp
where Temperature > yt and datediff(RecordDatam,yd) = 1;