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30 Day SQL Interview Prep Challenge Course

Master the SQL Skills Most Tested in Data Engineering, Analytics, BI, and Data Science Interviews — One Day at a Time

Course Summary

30-Day SQL Interview Prep Challenge is a structured, hands-on program designed to take you from SQL fundamentals to advanced interview-level problem solving in just 30 days.

Whether you're an aspiring Data Engineer, Data Analyst, BI Developer, ETL Developer, Database Professional, or software professional looking to strengthen your SQL skills, this challenge provides a practical roadmap to build real interview confidence through daily learning and practice.

Unlike traditional SQL courses that focus heavily on syntax, this challenge is built around how SQL is actually tested in technical interviews and used in real-world data environments.

Over 30 days, you will progressively master:

SELECT, WHERE, ORDER BY
GROUP BY and HAVING
Joins and Self Joins
NULL handling
Subqueries
CASE WHEN logic
Window Functions
Ranking Functions
LAG and LEAD
Running Totals
Moving Averages
Common Table Expressions (CTEs)
Deduplication Techniques
Date and Time Functions
String Manipulation
Advanced Aggregations
UNION, INTERSECT, and EXCEPT
Top-N Per Group Problems
Gaps and Islands
Pivot and Unpivot
Many-to-Many Relationships
Recursive CTEs
Query Performance Thinking
Advanced Interview Problem Solving

Each day includes:

Concept explanations in simple language
Real-world business scenarios
Visual understanding of SQL behavior
Interview-focused practice problems
Progressive difficulty levels
Hands-on coding exercises
Expert-level challenge questions

By the end of the challenge, you will be able to confidently solve many of the SQL patterns commonly seen in Data Engineering, Analytics, Data Science, and Business Intelligence interviews, while developing the analytical thinking required to tackle unfamiliar SQL problems under interview pressure.

If you can commit just 45–60 minutes a day for 30 days, this challenge can help transform SQL from a weakness into one of your strongest technical skills.

Course Curriculum

Start here!
1 Lesson
- 30 days from now, you will either crack the interview or make the same excuse.
  Preview
Part 1
8 Lessons
- Day 0 Why SQL Is the Most Valuable Skill You Can Learn.
  Start
- Day 1 SELECT, WHERE, ORDER BY
  Start
- Day 2 GROUP BY & HAVING
  Start
- Day 3 JOINs — INNER, LEFT, RIGHT & FULL
  Start
- Day 4 Working with NULLs
  Start
- Day 5 SELF JOIN — a table joining itself
  Start
- Day 6 Subqueries — queries inside queries
  Start
- Stop. Look Back Before Moving Forward.
  Start
Part 2
11 Lessons
- This Is Where Most People Quit
  Start
- Day 7 CASE WHEN — conditional logic in SQL
  Start
- Day 8 ROW_NUMBER, RANK, & DENSE_RANK
  Start
- Day 9 PARTITION BY — scoping window functions
  Start
- Day 10 LAG & LEAD
  Start
- Day 11 SUM, AVG, COUNT as window functions
  Start
- Day 12 FIRST_VALUE, LAST_VALUE, NTH_VALUE
  Start
- Day 13 NTILE & PERCENT_RANK
  Start
- Day 14 Window Frames — ROWS vs RANGE BETWEEN
  Start
- Day 15 CTEs — Common Table Expressions
  Start
- You Are Further Ahead Than You Think
  Start
Part 3
9 Lessons
- This is where your SQL becomes genuinely powerful.
  Start
- Day 16 Chained CTEs — Building Logic Step by Step
  Start
- Day 17 Deduplication — Keeping the Right Record
  Start
- Day 18 Date & Time Functions — Arithmetic on the Calendar
  Start
- Day 19 String Functions — Cleaning Messy Text Data
  Start
- Day 20 Advanced Aggregation — FILTER and Conditional Counts
  Start
- Day 21 Set Operators — UNION, INTERSECT, EXCEPT
  Start
- Day 22 Top-N Per Group — ROW_NUMBER, RANK, DENSE_RANK
  Start
- You Are Closer Than Ever
  Start
Part 4
12 Lessons
- Do Not Slow Down Now
  Start
- How did this challenge feel for you so far?
  Start
- Day 23 Running Totals & Moving Averages
  Start
- Day 24 Gaps & Islands — Consecutive Sequence Detection
  Start
- Day 25 Pivot & Unpivot — Reshaping Tabular Data
  Start
- Day 26 Many-to-Many Joins & Bridge Tables
  Start
- Day 27 Recursive CTEs — Tree & Hierarchy Traversal
  Start
- Day 28 Query Performance — Writing SQL That Scales
  Start
- Day 29 Mixed Expert — No Labels. Two Problems.
  Start
- Day 30- 30 Days, Full-Stack SQL.
  Start
- Personal Request from me
  Start
- You are a Diamond!
  Start

Sachin Chandrashekhar

Lead Data Engineer @ World's #1 Airline

Hema Srinivas

Working as a Big Data Emgineer with 12 years of experience

John Smith

Developer

Highly Recommended Course. Easy to Understand, Informative, Very Well Organized. The Course is Full of Practical and Valuable for Anyone who wants to Enhance their Skills. Really Enjoyed it. Thank you!!

30 Day SQL Interview Prep Challenge Course

Master the SQL Skills Most Tested in Data Engineering, Analytics, BI, and Data Science Interviews — One Day at a Time

Course Summary

Course Curriculum

Start here!

Part 1

Part 2

Part 3

Part 4

Sachin Chandrashekhar

Hema Srinivas

John Smith

Highly Recommended Course. Easy to Understand, Informative, Very Well Organized. The Course is Full of Practical and Valuable for Anyone who wants to Enhance their Skills. Really Enjoyed it. Thank you!!

Course Pricing