Last Minute SQL Interview Prep Kit

By Ankit Bansal

Master essential database querying techniques and ace your upcoming data role interviews with this intensive rapid-revision guide. Tackle advanced scenarios including complex joins, window functions, time-series analysis, and data de-duplication to build absolute confidence before technical evaluations.

Table of Contents

Last Minute SQL Interview Prep Kit

Table of Contents

Introduction & De-duplication Strategies using CTEs

Set Operations: Deep Dive into UNION vs. UNION ALL

Subqueries and Joins for Departmental Filtering

Finding Nth Highest Salaries & Transaction Analysis

Conditional Data Manipulation with CASE WHEN

Join Mechanics: How SQL Handles Duplicate Keys

Outer Joins, Nulls, and Cartesian Products

Calculating Join Output Sizes and Edge Cases

Window Functions: ROW_NUMBER, RANK, and DENSE_RANK

Advanced Ordering and Partitioning in Window Functions

Solving the Top N Earners per Department Problem

Self-Joins: Mapping Employee-Manager Hierarchies

Comparing Employee Salaries to Manager Salaries

Data Pivoting and Unpivoting Techniques

Running Averages and Filtering with WHERE vs. HAVING

Top Products per Category & YoY Growth Analysis

Using LAG() and LEAD() for Trend Analysis

Rolling Sums and Moving Windows (ROWS BETWEEN)

Cross-Tabulation and Matrix Reporting in SQL

Date-Time Arithmetic: Calculating Employee Work Hours

Categorizing Employees by Work Hours (CASE Logic)

Finding Latest and Second Latest Software Runs

Sessionization Part 1: Defining Session Boundaries

Sessionization Part 2: Generating Session IDs

Project Budget Analysis: Prorating Salaries

Identifying Over-Budget Projects with Joins

Compounding Salary Promotions Over Time

Decimal Precision, Query Validation, and Wrap-Up