Week 2/32: SQL Fundamentals for Data Engineering Interviews

Week 2 of 32-Week Data Engineering Interview Guide

In our previous post, we explored the role of a Data Engineer and Data Engineering Interviews. Building on that foundation, we dive into SQL fundamentals in this post.

According to 2024 data from datanerd.tech¹, SQL is the most in-demand skill for Data Engineers and Senior Data Engineers across all countries, appearing in 66.8% and 72.4% of job postings, respectively. This highlights SQL's critical role in data engineering workflows and its importance in interviews.

To see the full plan for the series, visit:

Week 0/32 - A Comprehensive Data Engineering Interview Preparation Guide

What This Post Covers:

This post focuses on solving SQL interview questions inspired by challenges posed by top companies like KPMG, Amazon, Apple, Microsoft, Dell, and UnitedHealth. These questions are designed to test your technical understanding and hands-on query-writing skills. While the focus is primarily on Data Engineering interviews, we believe professionals preparing for roles like Data Analyst or Analytics Engineer will also find this post highly beneficial.

We assume you already have a foundational understanding of SQL. If you're new to SQL or want a quick refresher, we recommend starting with one of the below materials:

• SQL Tutorial by w3schools²

• SQL Tutorial by SQLZoo³

Topics included in this post:

1. JOINs

2. Aggregate Functions

3. Subqueries and Common Table Expressions (CTEs)

4. Date and Time Functions

5. NULL values

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