Deloitte

Deloitte

Multinational professional services network with offices in over 150 countries.

4 Rounds ~21 Days Medium
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The Interview Loop

Recruiter Screen (30 min)

Standard fit check, behavioral questions, and resume overview.

Technical Loop (3-4 Rounds)

Deep dive into domain knowledge, coding, and system design.

Interview Question Bank

Backend Engineer • Coding • medium

Write a SQL query to find employees who have the highest salary in each of the departments.

#Database #Joins #Group By
Practice
Backend Engineer • Coding • medium

Write a query to calculate the cumulative sum of revenue per month for a given client over the past year.

#Database #Window Functions #Aggregations
Practice
Backend Engineer • Coding • medium

Write a SQL query to find all overlapping date ranges for client project assignments in the Projects table.

#Database #Self Join #Date Functions
Practice
Backend Engineer • Coding • easy

Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id.

#Database #DELETE #Self Join
Practice
Backend Engineer • Coding • medium

Write a SQL query to report the nth highest salary from the Employee table. If there is no nth highest salary, the query should report null.

#Database #Window Functions #Subqueries
Practice
Data Engineer • Coding • medium

Write a SQL query to find the top 3 highest-paid employees in each department. If there is a tie, they should have the same rank.

#Window Functions #DENSE_RANK #Joins
Practice
Data Engineer • Coding • medium

Write a SQL query to calculate the cumulative sum of revenue per month for the year 2023.

#Window Functions #Aggregations
Practice
Data Engineer • Coding • medium

You have a table with millions of rows and no primary key. Write a SQL query to delete all duplicate rows, keeping only one instance of each.

#Data Cleansing #CTEs #ROW_NUMBER
Practice
Data Engineer • Coding • hard

Write a recursive CTE in SQL to output a company's organizational chart, showing each employee's name, their manager's name, and their depth level in the hierarchy.

#Recursive CTE #Hierarchical Data
Practice
Data Engineer • Technical • easy

Explain the difference between RANK(), DENSE_RANK(), and ROW_NUMBER() in SQL. Provide a brief example of when to use each.

#Window Functions
Practice
Data Engineer • Technical • medium

A client complains that a specific reporting query is taking 30 minutes to run. Walk me through your step-by-step approach to optimize this SQL query.

#Performance Tuning #Query Optimization
Practice
Data Scientist • Coding • medium

Write a SQL query to find the top 3 highest-paid employees in each department. Assume a table 'employees' with columns 'id', 'name', 'salary', and 'department_id'.

#Window Functions #Data Aggregation
Practice
Data Scientist • Coding • medium

Write a SQL query to calculate the rolling 7-day average of daily transaction volumes from a 'transactions' table.

#Window Functions #Time Series #Data Aggregation
Practice
Data Scientist • Coding • hard

Given a 'user_logins' table, write a SQL query to find the month-over-month retention rate of users.

#Cohort Analysis #Self Joins #Date Functions
Practice
Data Scientist • Technical • hard

How do you optimize a slow-running SQL query that joins multiple large tables (over 100 million rows each)?

#Query Optimization #Database Performance #Indexing
Practice
Data Scientist • Technical • easy

What is the difference between RANK(), DENSE_RANK(), and ROW_NUMBER() in SQL? Provide an example of when to use each.

#Window Functions #SQL Theory
Practice
Data Scientist • Technical • medium

How would you handle duplicate records in a massive SQL database without using the DISTINCT keyword?

#Data Cleaning #GROUP BY #Window Functions
Practice
Machine Learning Engineer • Coding • medium

Write a SQL query to find the top 3 highest paid employees in each department. This is a common requirement when analyzing client HR data.

#Window Functions #Subqueries #Data Aggregation
Practice
Product Manager • Coding • easy

Write a SQL query to find the top 3 clients by revenue in the last quarter, given a 'transactions' and 'clients' table.

#Data Extraction #Joins #Aggregations
Practice
Software Engineer • Coding • medium

Write a SQL query to find the second highest salary from an Employee table.

#Database #Queries #Aggregation
Practice
Software Engineer • Coding • easy

Write a SQL query to find employees who earn more than their managers.

#Database #Self Joins
Practice

Difficulty Radar

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The "Standard" Interviewer

Senior Engineer

Focuses on core competencies, system constraints, and clear communication.

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Think Out Loud

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