Rising Temperature SQL Challenge - Oracle Solution

1. Introduction

This blog post will cover how to find dates with higher temperatures than the previous day using an Oracle database. This query is often used in meteorological data analysis and climate studies.

Problem

We need to create an Oracle SQL query to identify all dates in the Weather table where the temperature was higher than on the previous date.

Database Table:

Weather Table:

id	recordDate	temperature
1	2020-01-01	10
2	2020-01-02	15

3. Oracle Solution

SELECT a.id
FROM Weather a
JOIN Weather b ON a.recordDate = b.recordDate + 1
WHERE a.temperature > b.temperature;

Output:

id
2

Explanation:

1. The query performs a self-join on the Weather table, with a being the current day and b the previous day.

2. It uses the condition a.recordDate = b.recordDate + 1 to ensure a's date is exactly one day ahead of b's date.

3. The WHERE clause filters for instances where a's temperature is higher than b's temperature.

4. The query returns the ids of the dates where the temperature was higher than the previous day, effectively capturing rising temperatures.