Data Scientist Data Manipulation (SQL/Python) Interview Questions
Practice 530 real Data Manipulation (SQL/Python) interview questions for Data Scientist roles. From companies including Meta, Amazon, TikTok, Capital One, DoorDash.
"I got asked a hardcore MCM DP question and I saw it on PracHub as well. Solved that question in 5 minutes. Without PracHub I doubt I could solve it in 5 hours. Though somehow didn't get hired, perhaps I guess I solved it too fast? /s"
"Believe me i'm a student here jn US. Recently interviewed for MSFT. They asked me exact question from PracHub. I saw it the night before and ignored it cause why waste time on random sites. I legit wanna go back and redo this whole thing if I had chance. Not saying will work for everyone but there is certainly some merit to that website. And i'm gonna use it in future prep from now on like lc tagged"
"10 years of experience but never worked at a top company. PracHub's senior-level questions helped me break into FAANG at 35. Age is just a number."
"I was skeptical about the 'real questions' claim, so I put it to the test. I searched for the exact question I got grilled on at my last Meta onsite... and it was right there. Word for word."
"Got a Google recruiter call on Monday, interview on Friday. Crammed PracHub for 4 days. Passed every round. This platform is a miracle worker."
"I've used LC, Glassdoor, and random Discords. Nothing comes close to the accuracy here. The questions are actually current — that's what got me. Felt like I had a cheat sheet during the interview."
"The solution quality is insane. It covers approach, edge cases, time complexity, follow-ups. Nothing else comes close."
"Legit the only resource you need. TC went from 180k -> 350k. Just memorize the top 50 for your target company and you're golden."
"PracHub Premium for one month cost me the price of two coffees a week. It landed me a $280K+ starting offer."
"Literally just signed a $600k offer. I only had 2 weeks to prep, so I focused entirely on the company-tagged lists here. If you're targeting L5+, don't overthink it."
"Coaches and bootcamp prep courses cost around $200-300 but PracHub Premium is actually less than a Netflix subscription. And it landed me a $178K offer."
"I honestly don't know how you guys gather so many real interview questions. It's almost scary. I walked into my Amazon loop and recognized 3 out of 4 problems from your database."
"Discovered PracHub 10 days before my interview. By day 5, I stopped being nervous. By interview day, I was actually excited to show what I knew."
"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
"The search is what sold me. I typed in a really niche DP problem I got asked last year and it actually came up, full breakdown and everything. These guys are clearly updating it constantly."
Compute invalid event percentage by pixel
Context You work on an ads pixel instrumentation platform. Each pixel emits events throughout the day; some events are missing (not observed) and some...
Calculate Pirated Usage and Revenue Loss
You are analyzing theme piracy on an e-commerce platform. Assume the analysis window is 2023-01-01 through 2023-12-31, all timestamps are stored in UT...
Analyze Document Collaboration CSVs
You are given two CSV files. document_activity.csv - page_id STRING — document identifier - user_id STRING — user who viewed or worked on the document...
Write SQL for rankings, state, and aggregations
You are given several independent datasets. For each dataset, write the required SQL query (ANSI SQL is fine). Assume dates are in UTC and DATE column...
Analyze document collaboration from CSV logs
You are given two CSV files exported from a document collaboration product. Data 1) doc_access.csv Each row represents a user accessing (viewing/editi...
Calculate Ultimate Loss by Policy Term
You work with insurance policy-term loss data. For a given policy term, its ultimate loss is defined as the sum of losses from the current term and al...
Justify and harden your analytics and BI stack
List your current analytics tech suite end-to-end (ingestion, storage/warehouse, transformation, orchestration, catalog/lineage, experimentation platf...
Write SQL to analyze response accuracy and speed
You are given response-level data for an online assessment with sections verbal/design/analytics and verbal subtypes grammar/vocab/tense/other. Using ...
Design MapReduce and Spark jobs
Big data systems: (a) Explain Hadoop’s fault tolerance (HDFS replication, task re-execution) and why MapReduce includes shuffling and sorting; in a wo...
Compute survey rates and bias-correct ratings
Today is 2025-09-01. Use the schema and sample data below to answer A and B with SQL (standard SQL; you may use CTEs and window functions). Assume tim...
Transform nested dicts with pandas apply/lambda
Given a pandas DataFrame df with columns: user_id (int), ts (datetime64[ns]), events (list of dicts), attrs (dict). Example rows (conceptual): user_id...
Compute ETA shift and conversion uplift
Use PostgreSQL (SQL) and brief Python pseudocode. Assume 'today' is 2025-09-01. Schema: - trips(trip_id BIGINT, request_ts TIMESTAMP, city_id INT, rid...
Write SQL to backtest refund policy
Using the schema and samples below, write a single SQL query (CTEs allowed) that does all of the following for the last 30 days relative to today = 20...
Design a data platform enablement
Design a pragmatic data‑platform enablement for a mid‑tier retail bank migrating to cloud under PII and data‑residency constraints. Describe the targe...
Compute CTR by format for new US users
You are given three tables. Write a single SQL query to compute click-through rate (CTR) by pin_format for NEW users in the US, where NEW users are th...
Analyze Driver Requests for Food Delivery Orders
ORDER_TABLE order_id | restaurant_id | created_at | total_value 1 | 101 | 2024-06-01 12:01 | 45.50 2 | 102 ...
Select Top Customers Using Transaction Data Filters
transactions +----+---------+------------+--------+ | id | user_id | order_date | amount | +----+---------+------------+--------+ | 1 | 101 | 202...
Count Article Types Viewed
Question You are given article view events and article metadata. Table 1: article_views — one row per article view event. | Column | Type | Descriptio...
Compute Cohort Retention Rate
You are given two tables: - users(user_id BIGINT, signup_ts TIMESTAMP) — one row per user. - user_activity(user_id BIGINT, activity_ts TIMESTAMP, even...
Find top-paid employee per department
Given the following tables: 1) employees - employee_id INT PRIMARY KEY - employee_name VARCHAR 2) employee_department - employee_id INT - department_i...