MediumNo. 2388LeetCode Premium
Change Null Values in a Table to the Previous Value — LeetCode 2388 Python Solution
- Topics
- Database
- Reading time
- 3 min
- Source
- leetcode.com
Table schema
Table: CoffeeShop +-------------+---------+ | Column Name | Type | +-------------+---------+ | id | int | | drink | varchar | +-------------+---------+ id is the primary key (column with unique values) for this table. Each row in this table shows the order id and the name of the drink ordered.Example
+-------------+---------+
| Column Name | Type |
+-------------+---------+
| id | int |
| drink | varchar |
+-------------+---------+
id is the primary key (column with unique values) for this table.
Each row in this table shows the order id and the name of the drink ordered. Some drink rows are nulls.Python solution
import duckdb
import pandas as pd
def solution(coffee_shop: pd.DataFrame) -> pd.DataFrame:
con = duckdb.connect()
con.register("CoffeeShop", coffee_shop)
return con.execute("""SELECT
id,
CASE
WHEN drink IS NOT NULL THEN @cur := drink
ELSE @cur
END AS drink
FROM CoffeeShop;""").df()Complexity
- Time
- O(n log n)(typical)
- Space · auxiliary
- O(n)
Related problems
| No. | Problem | Difficulty |
|---|---|---|
| 0175 | Combine Two Tables | Easy |
| 0176 | Second Highest Salary | Medium |
| 0177 | Nth Highest Salary | Medium |
| 0178 | Rank Scores | Medium |
| 0180 | Consecutive Numbers | Medium |
| 0181 | Employees Earning More Than Their Managers | Easy |
Frequently asked questions
- How hard is LeetCode 2388. Change Null Values in a Table to the Previous Value?
LeetCode 2388. Change Null Values in a Table to the Previous Value is rated Medium on LeetCode.
- What topics does LeetCode 2388. Change Null Values in a Table to the Previous Value cover?
LeetCode 2388. Change Null Values in a Table to the Previous Value is tagged Database on LeetCode.
- Is LeetCode 2388. Change Null Values in a Table to the Previous Value a premium problem?
Yes. LeetCode 2388. Change Null Values in a Table to the Previous Value is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.