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."
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 ...
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...
Write SQL to compute shop visibility share
Assume today is 2025-09-01. Compute the top 3 shops by average daily visibility share over the last 7 days (2025-08-26 to 2025-09-01, inclusive) for U...
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 SQL with HAVING and efficient joins
You are given two tables. Schema - interactions(product_id INT, buyer_id INT, seller_id INT, interaction_date DATE, interaction_type VARCHAR, interact...
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
Using pandas only (no loops over rows), write a function build_facts(customers, orders, order_items, products, payments, shipments, refunds) -> pd.Dat...
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...
Produce dating profile funnel report by cohort
You work on a dating app. Produce a daily profile-funnel report for 2025-08-25 through 2025-09-01 inclusive, with one row per day, gender, and age_buc...
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...
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...
Write SQL for 7-day WhatsApp call metrics
Today is fixed as 2025-09-01. Using PostgreSQL, write a single query that returns one row per UTC calendar date for the last 7 days inclusive of today...
Write SQL for revenue and advertiser analyses
Use the schema below and ANSI SQL. Treat “today” as 2025-09-01. Schema: - active_ads(date DATE, ad_id INT, advertiser_id INT, creation_source VARCHAR,...
Use pandas to aggregate, pivot, and label
Given two pandas DataFrames, write code to: (1) merge and aggregate revenue; (2) produce a 2x2 pivot; (3) compute per-state counts with value_counts, ...
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...