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 callers contacting >3 people last 7 days
Using the schema below, write a single SQL query to return the number of unique callers who started calls with more than 3 distinct other users during...
Load and visualize large CSV robustly
You're screen-sharing in a HackerRank environment with Python 3, pandas, numpy, seaborn, and matplotlib available. You are given a single file data.cs...
Write SQL for dedup and purchase shares
You are given two tables with intentional duplicates. Write SQL to: (a) identify duplicate user_ids and produce a canonical, deduplicated users set; (...
Write SQL to analyze Group Calls adoption
Write SQL (assume PostgreSQL) to analyze Group Calls adoption and cannibalization. Use this schema and sample data. Schema: - users(user_id INT PRIMAR...
Write SQL for initiators and French DAU%
You are given the following PostgreSQL tables. Assume all timestamps are UTC and "today" is 2025-09-01. For any reference to "last 7 days," use the in...
Design an analytic warehouse for event data
Design a warehouse-ready analytics data model and ingestion plan to support cohort retention, ARPU, and product-case analyses at scale (50M events/day...
Calculate cross-channel login user proportions
Write SQL to compute, for 2025-08-29 through 2025-08-31, the proportion of users who logged in only via mobile, only via desktop, and via both, where ...
Query seven-day conversion with windows and dedupe
Assume all timestamps are UTC. Treat "today" as 2025-09-01. Define "last 7 days" as the inclusive window [2025-08-26 00:00:00, 2025-09-01 23:59:59]. S...
Design metrics and write SQL for a case
Case: Measure the impact of outreach on subsequent purchases and diagnose anomalies. Define your primary metric and write SQL. Schema and tiny samples...
Write SQL for snapshot features and labels
Use 'today' = 2025-09-01. Invented schema (UTC): users(u_id INT, signup_dt DATE, country STRING) events(u_id INT, event_time TIMESTAMP, arrival_time T...
Write SQL for comment analytics
You are given the following schema and tiny sample data. Schema: - users(user_id INT PRIMARY KEY, country VARCHAR, created_at DATE) - posts(post_id IN...
Manipulate data in R with dplyr joins and windows
Using R and dplyr, answer the following using these small tables (dates are ISO strings): transactions(user_id, order_id, order_date, channel, amount)...
Write complex SQL for streaming funnels
You are analyzing a Disney/Hulu product funnel with events captured in a single table. Write ANSI-SQL (Snowflake/BigQuery compatible) to answer the su...
Design an idempotent churn ETL pipeline
You must build a daily pipeline that produces month-end churn metrics (logo churn, gross revenue churn, net revenue retention) from streaming subscrip...
Compute churn and revenue churn in SQL
You receive monthly end-of-month subscription snapshots and must compute August-2025 churn metrics. Schema and sample data: Table: subscription_monthl...
Write windowed retention and ARPU SQL
You are given three tables. Write one SQL script (CTEs allowed) that answers all parts using window functions and joins (no procedural loops): Schema:...
Audit and onboard unfamiliar datasets safely
You inherit unfamiliar hotel search data with sparse documentation. Provide a concrete, ordered checklist to: a) discover tables/columns and verify pr...
Design SQL/Pandas aggregations on retail schema
Using the schema and sample data below, answer both parts. Assume today is 2025-09-01. Use standard SQL (e.g., PostgreSQL) and idiomatic pandas withou...
Write monthly new-vs-returning requests SQL
Given the schema and sample data below, write a single PostgreSQL query (no dynamic SQL) that returns, for every calendar month present in requests, t...
Write complex joins and window functions
You are given a simplified Thumbtack-like marketplace schema in PostgreSQL. Assume UTC timestamps and weeks start on Monday. Treat "today" as 2025-09-...