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 same-day acceptance metrics last week
Assume today is 2025-09-01; interpret 'last week' as 2025-08-25 through 2025-08-31 inclusive, using UTC dates. You have the following schema and sampl...
Manipulate data efficiently in Python
Answer the following: (a) Contrast list comprehensions and generators with respect to memory and evaluation; write a generator that yields rolling win...
Query conversion and retention with SQL windows
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Write SQL and Python for funnels/retention
Given the following schema and small samples, answer Parts A–C. Assume timestamps are UTC and "today" is 2025-09-01. Schema: users(id INT, country STR...
Match requests and accepts into friendships in SQL
Given two event tables, write a single SQL query (PostgreSQL) to output unique undirected friendships with the earliest valid friendship_date. Schema ...
Write SQL for shop visibility and activity metric
Assume 'today' is 2025-09-01. Schema and tiny samples: 1) shops(shop_id INT, created_at DATE) Sample: shop_id | created_at 1 | 2025-08-25 2 | 2025...
Clean and aggregate factory event data in Pandas
You are given three Pandas DataFrames for a factory: (1) events[event_id, machine_id, ts_utc (datetime64[ns, UTC]), event_type in {'start','stop','fau...
Transform event logs with subscription windows in pandas
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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...
Transform messy transactions with pandas
You are given two CSVs. transactions.csv - Columns: txn_id, user_id, ts_iso (ISO8601 with timezone), amount (decimal USD; refunds negative), merchant_...
Write SQL for noisy A/B launch metrics
PostgreSQL. Today is 2025-09-01. You’re given the following schema and toy samples: users(user_id INT, country TEXT, signup_date DATE, marketing_chann...
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 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...
Write SQL window functions for streaks
Assume today is 2025-09-01. Using standard SQL (e.g., PostgreSQL), answer the following using window functions only (no procedural loops, no correlate...
Write rolling-window SQL over weekly cohorts
You have two tables: users and transactions. Write a single SQL query (use CTEs) to produce, for each calendar week and user, weekly_revenue, a 4-week...
Write SQL to detect recurring non-subscription users
You have two tables: merchant and transaction. Assume 'today' is 2025-09-01. Schema: merchant(merchant_id INT PK, merchant_name TEXT, country TEXT, cr...
Merge seven tables into one clean DataFrame
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Query top spenders and 7-day growth
Assume 'today' = 2025-09-01. Write a SQL query to: (1) for each model, compute total revenue in the last 7 days (2025-08-26 to 2025-09-01 inclusive) a...
Manipulate and merge DataFrames correctly
Given three pandas DataFrames: customers customer_id, join_date, tier 101, 2025-01-02, gold 102, 2025-02-10, silver 103, 2025-03-05, gold products mod...
Compute French DAU video-call percentage yesterday
Compute the percentage of daily active users (DAU) from France who were on at least one video call yesterday (2025-08-31 UTC). DAU is defined as users...