Data Analyst • Coding • medium

Write a SQL query to calculate month-over-month revenue growth.

#Revenue #Growth Analytics

Practice

Data Analyst • Coding • medium

Explain window functions. Write a query using LAG() to compute day-over-day change.

#Window Functions

Practice

Data Analyst • Coding • hard

How would you detect anomalies in a daily revenue time series using SQL?

#Anomaly Detection #SQL

Practice

Data Analyst • Coding • hard

Write a SQL query to calculate the rolling 28-day average session duration per user.

#Rolling Average #Sessions

Practice

Data Analyst • Coding • medium

What is a pivot table in SQL? How would you implement it without native PIVOT support?

#Pivot #Data Transformation

Practice

Data Analyst • Coding • hard

What is a funnel query? Write one for a 3-step user onboarding flow.

#Funnel Analysis

Practice

Data Analyst • Coding • hard

Write a SQL query to find customers who made purchases in both January and February but not March.

#Set Operations

Practice

Data Analyst • Coding • hard

How would you build a cohort analysis for user retention in SQL?

#Cohort Analysis #Retention

Practice

Data Analyst • Technical • medium

How do you handle timezone conversions in SQL analytics?

#Timezones #Analytics

Practice

Data Analyst • Technical • easy

Explain the difference between a HAVING clause and a WHERE clause.

#SQL Basics

Practice

Data Engineer • Coding • medium

Given a `user_logins` table with `user_id` and `login_date`, write a SQL query to calculate the 7-day rolling average of Daily Active Users (DAU) for the last 30 days.

#Window Functions #Rolling Averages #DAU

Practice

Data Engineer • Coding • medium

Write a SQL query to find users who have interacted with a Meta ad and subsequently made a purchase on the advertiser's website within 24 hours. You have an `ad_clicks` table and a `conversions` table.

#Joins #Date/Time Functions #Attribution

Practice

Data Engineer • Coding • hard

Write a SQL query to calculate the retention rate of new users on a 1-day, 7-day, and 30-day basis. You are given a `user_activity` table with `user_id` and `activity_date`.

#Cohort Analysis #Retention #Self Joins #Conditional Aggregation

Practice

Data Engineer • Coding • medium

Write a SQL query to compute a 7-day rolling average of daily sales.

#Window Functions #Analytics

Practice

Data Engineer • Coding • medium

Write a SQL query to find the second highest salary per department.

#Window Functions #SQL

Practice

Data Engineer • Coding • easy

Given a `friend_requests` table (sender_id, receiver_id, date, status) and an `acceptances` table, write a SQL query to find the overall acceptance rate of friend requests by date.

#Joins #Aggregations #Ratios

Practice

Data Engineer • Technical • medium

Explain the difference between OLAP and OLTP systems. When would you use each?

#OLAP #OLTP #Databases

Practice

Data Engineer • Technical • hard

How would you optimize a SQL query that is running slowly on a 1 billion row table?

#Query Optimization #Indexing

Practice

Data Engineer • Technical • medium

Explain the difference between RANK(), DENSE_RANK(), and ROW_NUMBER().

#Window Functions #SQL

Practice

Data Engineer • Technical • medium

What is a materialized view? How does it differ from a regular view?

#Materialized Views #Performance

Practice

Data Engineer • Technical • medium

What are CTEs (Common Table Expressions) and how do they differ from subqueries?

#CTEs #SQL

Practice

Data Scientist • Coding • medium

Write a query to identify duplicate records and deduplicate them.

#Deduplication #Data Quality

Practice

Data Scientist • Coding • hard

Given a table `friend_requests` (sender_id, receiver_id, date, status), write a SQL query to calculate the overall friend acceptance rate for each day. Note that a request sent on day 1 might be accepted on day 3.

#Self Joins #Window Functions #Ratio Calculation

Practice

Data Scientist • Coding • medium

Write a SQL query to calculate the 7-day rolling retention rate of users who signed up through a specific marketing campaign. You have a `users` table (user_id, signup_date, campaign_id) and a `user_activity` table (user_id, activity_date).

#Retention #Rolling Metrics #Joins

Practice

Data Scientist • Coding • hard

How would you write a funnel analysis query in SQL?

#Funnel #Analytics

Practice

Data Scientist • Coding • hard

Write a SQL query to calculate 30-day user retention.

#Retention #Analytics

Practice

Data Scientist • Coding • medium

Given two tables: `ad_campaigns` (campaign_id, advertiser_id, spend) and `ad_clicks` (click_id, campaign_id, user_id, timestamp), write a SQL query to find the top 5 advertisers with the highest number of clicks per dollar spent who have spent at least $10,000 in the last 30 days.

#Joins #Aggregations #Date Functions

Practice

Data Scientist • Technical • easy

Explain the difference between INNER JOIN, LEFT JOIN, and CROSS JOIN.

#Joins #SQL

Practice

Product Manager • Coding • medium

Write a SQL query to find the top 10% of users by engagement (defined as messages sent) on Facebook Marketplace over the last 30 days.

#Window Functions #Data Analysis #Marketplace

Practice

Meta

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Interview Question Bank

Write a SQL query to calculate month-over-month revenue growth.

Explain window functions. Write a query using LAG() to compute day-over-day change.

How would you detect anomalies in a daily revenue time series using SQL?

Write a SQL query to calculate the rolling 28-day average session duration per user.

What is a pivot table in SQL? How would you implement it without native PIVOT support?

What is a funnel query? Write one for a 3-step user onboarding flow.

Write a SQL query to find customers who made purchases in both January and February but not March.

How would you build a cohort analysis for user retention in SQL?

How do you handle timezone conversions in SQL analytics?

Explain the difference between a HAVING clause and a WHERE clause.

Given a `user_logins` table with `user_id` and `login_date`, write a SQL query to calculate the 7-day rolling average of Daily Active Users (DAU) for the last 30 days.

Write a SQL query to find users who have interacted with a Meta ad and subsequently made a purchase on the advertiser's website within 24 hours. You have an `ad_clicks` table and a `conversions` table.

Write a SQL query to calculate the retention rate of new users on a 1-day, 7-day, and 30-day basis. You are given a `user_activity` table with `user_id` and `activity_date`.

Write a SQL query to compute a 7-day rolling average of daily sales.

Write a SQL query to find the second highest salary per department.

Given a `friend_requests` table (sender_id, receiver_id, date, status) and an `acceptances` table, write a SQL query to find the overall acceptance rate of friend requests by date.

Explain the difference between OLAP and OLTP systems. When would you use each?

How would you optimize a SQL query that is running slowly on a 1 billion row table?

Explain the difference between RANK(), DENSE_RANK(), and ROW_NUMBER().

What is a materialized view? How does it differ from a regular view?

What are CTEs (Common Table Expressions) and how do they differ from subqueries?

Write a query to identify duplicate records and deduplicate them.

Given a table `friend_requests` (sender_id, receiver_id, date, status), write a SQL query to calculate the overall friend acceptance rate for each day. Note that a request sent on day 1 might be accepted on day 3.

Write a SQL query to calculate the 7-day rolling retention rate of users who signed up through a specific marketing campaign. You have a `users` table (user_id, signup_date, campaign_id) and a `user_activity` table (user_id, activity_date).

How would you write a funnel analysis query in SQL?

Write a SQL query to calculate 30-day user retention.

Given two tables: `ad_campaigns` (campaign_id, advertiser_id, spend) and `ad_clicks` (click_id, campaign_id, user_id, timestamp), write a SQL query to find the top 5 advertisers with the highest number of clicks per dollar spent who have spent at least $10,000 in the last 30 days.

Explain the difference between INNER JOIN, LEFT JOIN, and CROSS JOIN.

Write a SQL query to find the top 10% of users by engagement (defined as messages sent) on Facebook Marketplace over the last 30 days.

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