SQL Interview Questions

Q: What are the most common SQL interview questions?

The most common SQL interview questions test JOINs (INNER, LEFT, RIGHT), window functions (ROW_NUMBER, RANK, LAG/LEAD), aggregations (GROUP BY, HAVING), CTEs and subqueries, and CASE WHEN statements. Companies like Meta, Google, and Amazon frequently ask about deduplication, top-N per group, and funnel analysis patterns.

Q: How should I prepare for SQL interviews at FAANG companies?

Focus on mastering window functions, complex JOINs, and CTEs. Practice 50-100 Medium difficulty problems, timing yourself to solve each in 15-20 minutes. Learn company-specific patterns: Meta emphasizes metrics and user behavior analysis, Amazon tests data aggregation and reporting, Google focuses on analytical thinking with SQL. Practice explaining your thought process out loud.

Q: What difficulty level should I practice for SQL interviews?

Start with Easy problems to build confidence and master fundamentals. Focus 70% of your time on Medium difficulty, which represents most real interview questions. Practice Hard problems if interviewing for senior roles (L5+) or companies known for difficult technical screens like Meta or Google. Aim to solve Medium problems in 15-20 minutes.

Q: Are SQL interviews the same for Data Scientists and Data Analysts?

Both roles are tested on SQL fundamentals, but with different emphasis. Data Scientists face more complex analytical queries involving statistical calculations, user cohorts, and A/B testing analysis. Data Analysts are tested more on reporting queries, business metrics, and dashboard-ready outputs. Data Scientists typically get 1-2 harder SQL problems, while Analysts may get 2-3 medium problems in the same time.

Q: Can I use online resources during SQL interviews?

Most companies (Meta, Google, Amazon, Netflix) do NOT allow internet access during SQL interviews. You're expected to write queries in shared editors like CoderPad without running them. Exceptions include Robinhood and DoorDash which allow searching, but relying on search wastes valuable time. Practice writing syntactically correct SQL without auto-complete or execution.

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SQL Interview Questions

SQL Interview Questions

All SQL Questions

Merge overlapping intervals per group in pandas

Analyze Mission Outcomes and Allocate Response Units

Analyze a Regression Dataset and Build a Safe File-Processing Utility

Analyze Pirated Theme Usage

Implement a Safe Average Function in Python

Write SQL for repeat churn

Find Values Owned Only by the Selected User

Analyze Pirated Theme Usage Impact

Compute Ride Metrics in SQL

SQL: Top 5 Vehicle Models by Miles per kWh Under a Maintenance Cost Cap

Compare Survey Satisfaction for New and Established Users

Number Entries Within Each Conversation

Analyze Returning Borrowers Across Two Days of Logs

Find Users with Seven Consecutive Impression Days

Continue Entry Numbers for a Daily Incremental Batch

Count Users Active After Signup

Calculate Daily Survey Response Rates by Country

Reason About Composite Join Keys and Predicate Placement

Rank Departments by Student Count

SQL: Users With No Rides in the Most Recent 7-Day Window, Including Non-Riders

Aggregate User Events and Check Join Uniqueness

SQL: Zero-Filled DAU, Rolling 30-Day MAU, and the MAU Impact of a User-ID Rehash

Rank Customers by Monthly Revenue with Competition Ties

Explore Employee and Session Audit Tables Before Analysis

Measure Customers Ordering from Bottom-Quartile Restaurants

Define and Analyze Early Engagement

Return Every Employee with a Mapped or Default Unique ID

Calculate the Median House Price in Each City

Single-Pass Python Cleaning Pipeline for Million-Document Web Crawl Parquet Files

Longest Meeting-Free Business-Hours Block per Employee and Day

SQL: Average Ride Rating in Users' First and Third Active Months by City

Calculate Average Camera Switches per Session

Estimate Page-Visit Duration from the Next User Event

Find the Longest Calendar-Day Streak with All Employees Present

Analyze User Ride Activity with SQL

SQL: Count Users With Zero or One Rides per City

Reconcile Monthly Bank-Account Balances Across Two Datasets

Calculate First-Week Retention by Signup Cohort

Load Daily JSONL LLM Chat Logs Into a Warehouse: Schema, Validation, Dedup, Idempotency

Compute a Rolling Seven-Day Revenue Sum with Missing Dates

Find Hosts Meeting Listing, Rating, and Review-Coverage Rules

Compare First-Week Retention by Plan Type

Sum Employee Working Time from Ordered Check-In and Check-Out Events

SQL: Monthly Ride Totals and Average Ratings, Newest Month First

Find the Latest Balance for a Bank Account

Count Users Retained on Day Seven

Calculate the Percentage of Highly Active Users by Country

Calculate the 2023 Session Signup Rate

Classify Tree Nodes in SQL

Model Data for Analytics, Reporting, and Applications

How to Prepare for SQL Interviews

Master the Core Concepts

Common Patterns You'll See

Practice with Real Company Questions