Data Scientist Data Manipulation (SQL/Python) Interview Questions
Practice 550 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."
Find top-spend categories per customer with ranking
Using the schema and sample data below, write a single ANSI SQL query (CTEs allowed; no temp tables) that returns, for each customer, their top 2 prod...
Compute unread and multi-account user percentages
You’re given two tables. Write ANSI-SQL to answer parts (a)–(d). Treat a notification as unread if read_at IS NULL. Denominator for user-level percent...
Compute monthly CRR with merges and gaps
You are given PostgreSQL tables user_profile(user_id, signup_ts, country, is_employee, is_test), user_events(user_id, event_ts, event_type, revenue, p...
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...
Deduplicate events and rank products with SQL
You are given two tables. Schema: - events(event_id INT PRIMARY KEY, user_id INT, product_id INT, event_time TIMESTAMP, idempotency_key TEXT, amount_c...
Write SQL for hashtag analytics and joins
Assume today = 2025-09-01. Schema and small sample data are below. Use ANSI SQL; explain any dialect-specific functions you choose. Where asked, expla...
Write SQL to localize anomaly and funnel
Given the schema and toy data below, write SQL to (a) validate instrumentation vs behavior change, (b) localize the 2025-09-01 Likes drop by app_versi...
Aggregate radiology spend and derive fiscal month
Using Python/pandas, complete the tasks below. Assume the following CSV-like input, where service_dt is object dtype and amounts may be negative (adju...
Analyze time-zoned events with pandas
You are given two pandas DataFrames. events columns: user_id:int, ts:str ISO-8601 with timezone (e.g., '2025-08-31T23:58:43-07:00'), event:str in {'si...
Write SQL for 7-day geo-localized revenue dashboard
Write a single SQL query (assume PostgreSQL; tz_offset is an integer hour offset from UTC) to compute a 7-day dashboard by local user date for US vs A...
Transform retail data with pandas groupby/merge/concat
Using pandas only (groupby/agg/merge/concat; no for-loops), write code to answer the sub-questions below on the following small dataframes. Assume tim...
Label new vs old users over time in SQL
Define users as “new” during the first 30 days inclusive after their signup_date, and “old” thereafter. Produce per-user, per-day labels over a window...
Write SQL to compute max-overlap lists
Invented schema and sample data below. Assume 'today' is 2025-09-01 and 'last 7 days' means 2025-08-26 through 2025-09-01 inclusive. Only consider lis...
Write SQL for engagement and attribution KPIs
Using the schema and sample data below, answer the SQL tasks. Assume timestamps are UTC and comments with is_deleted=1 do not count. Schema: users(use...
Compute and rank top bad advertisers
SQL on ad safety. Assume the following schema and sample rows. Use ANSI SQL. Today is 2025-09-01; interpret “last 7 days” as 2025-08-26 00:00:00 to 20...
Implement R dplyr simulation and left join
Using R and dplyr, run a simulation and a join. Data: prices item_id | price_usd 1 | 10.00 2 | 20.00 3 | 30.00 4 | 40.00 catalog item_id | category 1 ...
Verify subscriptions and analyze orders with SQL/Python
You are given two tables. Write SQL and Python (pandas) to answer the sub-questions precisely, handling edge cases, ties, and missing data. Schema - s...
Calculate posts per DAU by country today
Given two tables: - user_activity(user_id INT, activity_date DATE, country STRING, dau_flag TINYINT CHECK(dau_flag IN (0,1))) - composer(user_id INT, ...
Compute daily post success rate for last 7 days
You have a table composer(user_id INT, event STRING CHECK(event IN ('enter','post','cancel')), event_date DATE). Compute the post success rate for eac...
Write SQL for geo posting-frequency drops
Using the schema below, write a single ANSI SQL query (window functions allowed) that identifies countries with the largest share of creators whose po...