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."
Write conditional aggregates with CASE WHEN
Write conditional aggregates with CASE WHEN Write a query that produces conditional aggregates using CASE WHEN (e.g., counts of approved vs declined t...
Find recommended friend pairs by shared songs
You work on a music app and want to recommend “friend” connections based on listening similarity. Assume the following tables (all timestamps are in U...
Compute reply-based user metrics in 7 days
You are analyzing discussions on a social platform. Tables all_post - post_id (BIGINT, PK) - post_author_id (BIGINT, FK → user.user_id) - post_creatio...
Calculate User Registration Date and 7-Day Retention Rate
user_posts +---------+--------------+-----------+ | user_id | posting_date | num_posts | +---------+--------------+-----------+ | 1 | 2023-01-01...
Analyze Global Engagement and Impressions with SQL Queries
impressions +---------+---------+----------+----------------+ | user_id | country | category | impression_cnt | +---------+---------+----------+------...
Determine Maximum Consecutive Order Days Per User
Determine Maximum Consecutive Order Days Per User orders +----+---------+------------+ | id | user_id | order_date | +----+---------+------------+ | ...
Design Schema and Logic for Subscription Event Tracking
user_subscription_events +----------+-------------+---------------------+-----------+---------+ | user_id | event_type | event_time | plan_...
Calculate January-2024 SF Promotion Impact Using SQL Queries
campaign_users +---------+-----------+ | user_id | treatment | +---------+-----------+ | 1001 | control | | 1002 | test | | 1003 | con...
Compute percent of active users with 50+ calls
Problem You work on a Messenger-like app. You want to measure how many active users in Great Britain (GB) today have been heavy callers recently. Tabl...
Count weekly customers with ≥$1000 YTD spend
Question You are given a transaction-level table and must compute a weekly time series of how many customers have reached a year-to-date spending thre...
Compute monthly signups, conversion, and YoY growth
You work at a subscription company and are given a user-level table. Table company_users - id (INT, PK) — user/customer id - signup_date (DATE) — date...
Compute early signals for user retention
You are given two tables that track signups and user transactions. Tables users - user_id (STRING, PK) — unique user - signup_ts (TIMESTAMP) — time th...
[SQL] Job Ad Metrics with Applicant Filter
Job Ad Metrics Analysis Task Table Structure Table: job_activity job_id INT candidate_id INT activity_type VARCHAR -- can be 'view' or 'apply' Requi...
Write SQL to compare social-only vs game-only engagement
You are given two tables capturing Oculus app usage. Define an 'active day' as a UTC date on which a user generates at least one event. Consider only ...
Reconcile ledgers with SQL/Python and late events
You own a daily ETL + reconciliation job between two financial ledgers. Late postings (“delay time”) up to 48 hours are common. Schema: - payments_raw...
Define and query shop visibility
You are given the following schema. Use only the columns provided; do not introduce new fields or labels. Tables and columns: - shops(shop_id INT, sho...
Design an idempotent SQL ETL for late data
You own the daily_user_metrics fact table. Build an idempotent, rerunnable ETL that can be triggered for any date D and correctly handles duplicates, ...
Compute join counts and window ranks
Given the following small schema and data, answer all parts precisely and justify each count/output. Tables and rows: Customers(cust_id INT PRIMARY KE...
Transform clickstream with pandas sessionization
Given a pandas DataFrame events with columns [user_id:int, ts:str ISO8601 or NaT, url:str, server_log_ts:datetime], build 30-minute inactivity session...
Write SQL for cohort retention and ARPU
Using PostgreSQL, compute monthly signup cohort D30 retention and 30-day ARPU. Cohort month = date_trunc('month', signup_date). D30 retention = users ...