题目:
给定一个 Weather 表,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。
+---------+------------------+------------------+
| 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 |
+---------+------------------+------------------+
例如,根据上述给定的 Weather 表格,返回如下 Id:
+----+
| Id |
+----+
| 2 |
| 4 |
+----+
SQL架构:
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 Weather (Id, RecordDate, Temperature) values ('4', '2015-01-04', '30');
解题语句:
SELECT
t.Id
FROM
Weather AS t
LEFT JOIN Weather AS y ON TO_DAYS( t.RecordDate ) - TO_DAYS( y.RecordDate ) = 1
WHERE
t.Temperature > y.Temperature;