문제
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| Table: Weather
+---------------+---------+
| Column Name | Type |
+---------------+---------+
| id | int |
| recordDate | date |
| temperature | int |
+---------------+---------+
id is the primary key for this table.
This table contains information about the temperature on a certain day.
|
Write an SQL query to find all dates’ Id with higher temperatures compared to its previous dates (yesterday).
Return the result table in any order.
The query result format is in the following example.
입출력 예
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| Input:
Weather table:
+----+------------+-------------+
| id | recordDate | temperature |
+----+------------+-------------+
| 1 | 2015-01-01 | 10 |
| 2 | 2015-01-02 | 25 |
| 3 | 2015-01-03 | 20 |
| 4 | 2015-01-04 | 30 |
+----+------------+-------------+
Output:
+----+
| id |
+----+
| 2 |
| 4 |
+----+
Explanation:
In 2015-01-02, the temperature was higher than the previous day (10 -> 25).
In 2015-01-04, the temperature was higher than the previous day (20 -> 30).
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풀이
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| SELECT next.id
FROM Weather AS prev
JOIN Weather AS next
ON (prev.recordDate = SUBDATE(next.recordDate, 1)) AND
(prev.temperature < next.temperature);
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| SELECT *
FROM Weather AS prev
JOIN Weather AS next ON DATEDIFF(next.recordDate, prev.recordDate) = 1
WHERE prev.temperature < next.temperature;
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