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Quick Recall

496 interview recall cards and interactive SQL exercises for rapid prep

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Practice questions relevant for roles at

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Coinbase
Salesforce
Snap
PayPal
Robinhood
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TikTok
Target
Adobe
Tesla
Google
Meta
Amazon
Netflix
Uber
Stripe
Goldman Sachs
JPMorgan Chase
Airbnb
Spotify
Microsoft
LinkedIn
Apple
DoorDash
Coinbase
Salesforce
Snap
PayPal
Robinhood
Disney+
TikTok
Target
Adobe
Tesla
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Recall Cards
Practice

Write SQL & Python. Get Graded Instantly.

1,500+ problems on real industry datasets — graded in your browser in milliseconds. No backend, no waiting.

15 Industry Datasets·4 Difficulty Levels·Instant Feedback
query.sql ACCEPTED
SELECT
  c.campaign_name,
  SUM(i.cost) AS total_spend,
  COUNT(DISTINCT cl.click_id) AS clicks
FROM campaigns c
JOIN impressions i ON c.id = i.campaign_id
LEFT JOIN clicks cl ON i.id = cl.impression_id
WHERE c.status = 'active'
GROUP BY c.campaign_name
ORDER BY total_spend DESC;
3 rows · 6ms
campaign_nametotal_spendclicks
Holiday Push42,8501,247
Brand Awareness38,200982
Retarget Q425,600654
solve.py ACCEPTED
import pandas as pd
import numpy as np
def solve(campaigns, impressions, clicks):
  active = campaigns[campaigns['status'] == 'active']
  df = (active
    .merge(impressions, on='campaign_id')
    .merge(clicks, on='impression_id', how='left'))
  return (df
    .groupby('campaign_name')
    .agg(total_spend=('cost','sum'), clicks=('click_id','nunique'))
    .sort_values('total_spend', ascending=False)
    .reset_index())
3 rows · 42ms
campaign_nametotal_spendclicks
Holiday Push42,8501,247
Brand Awareness38,200982
Retarget Q425,600654
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Recall

Sharpen Your Knowledge, Fast

Two ways to drill interview-critical concepts: swipe-based recall cards across 5 categories, and hands-on SQL exercises with a live editor.

Interview Recall Cards

496 cards · 5 categories · Swipe to master

Start
SQL
96 cards
JoinsWindow FnsCTEsAggregations
Python & Pandas
111 cards
OOPDataFramesNumPyFile I/O
Statistics
83 cards
HypothesisBayesianA/B TestsProbability
Machine Learning
117 cards
Deep LearningFeature EngMLOpsEvaluation
LLMs & GenAI
89 cards
RAGFine-tuningAgentsPrompting

SQL Exercises

66 lessons · 284 exercises · Live SQL editor

Start
1
Foundations
SELECT, WHERE, ORDER BY
2
Joins
INNER, LEFT, Self Joins
3
Aggregations
GROUP BY, HAVING, COUNT
4
Window Fns
ROW_NUMBER, RANK, LAG
5
CTEs
WITH, Recursive CTEs
6
Subqueries
Correlated, EXISTS
7
CASE Logic
CASE WHEN, COALESCE
8
Date & Time
Date Fns, Time Periods
9
String & Sets
UNION, String Fns
10
Advanced
Top-N, Pivoting, Series
11
Optimization
Indexes, Anti-patterns
Learn

4 Interactive Courses, Completely Free

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15 Industry Domains

Practice on data modeled after real companies.

Ad Tech
Banking
Fintech
Health
Lodging
Logistics
Food Delivery
Mobility
Payments
Real Estate
Retail
SaaS
Social
Streaming
Telecom

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