Find Days Warmer Than Their Actual Previous Calendar Day
Company: Amazon
Role: Software Engineer
Category: Data Manipulation (SQL/Python)
Difficulty: easy
Interview Round: Other
### Problem
Return the id of each Weather row whose temperature exceeds the temperature on the immediately preceding calendar date. A previous stored row separated by a date gap is not yesterday. Result ordering is unrestricted.
### Tables
Table: `Weather`
```text
+---------------+---------+
| Column Name | Type |
+---------------+---------+
| id | int |
| recordDate | date |
| temperature | int |
+---------------+---------+
id is the column with unique values for this table.
There are no different rows with the same recordDate.
This table contains information about the temperature on a certain day.
```
### Example
```text
Weather (id,recordDate,temperature): (4,2021-02-01,8), (9,2021-02-02,12), (10,2021-02-04,20), (11,2021-02-05,20)
Output (id): (9)
```
### What a Strong Answer Covers
- Use calendar dates, including gaps between stored observations.
- Keep only strictly warmer observations and return the requested ID.
- Explain the handling of equal temperatures and missing dates.
### Follow-up Questions
- What changes if the comparison is with the most recent recorded date?
- What result should an example spanning December 31 and January 1 produce?
Overview: Return the id of each Weather row whose temperature exceeds the temperature on the immediately preceding calendar date. A previous stored row separated by a date gap is not yesterday. Result ordering is unrestricted.
