SQL Interview Prep – Class 6 | DISTINCT, UNION & Top 10 Questions

Описание: Welcome to SQL Class 6 of our Beginner-to-Job-Ready SQL Series!
This session is interview-focused and highly practical, covering unique data retrieval, UNION operations, and the Top 10 SQL interview questions for Data Engineering roles.

⭐ What you’ll learn in this class:
🔹 1. Working with Unique Data

What is DISTINCT in SQL?

How to remove duplicate records

Using DISTINCT with single & multiple columns

Performance tips and common mistakes

🔹 2. UNION & UNION ALL

What is UNION?

Difference between UNION vs UNION ALL

Rules for using UNION

Real-world examples from reporting & data pipelines

🔹 3. Top 10 SQL Interview Questions (Data Engineering)

DISTINCT vs GROUP BY

UNION vs JOIN

DELETE vs TRUNCATE vs DROP

Primary Key vs Unique Key

OLTP vs OLAP

Subquery vs CTE

Index basics

NULL handling

Real-time query scenarios

Interview tips & best practices

🎯 Who should watch this?

Freshers preparing for SQL & Data Engineering interviews

Working professionals upgrading data skills

Data analysts moving into data engineering

Students targeting roles in:
Data Engineering, Data Analytics, Backend Development, BI & Cloud

🚀 Why this class is important?

DISTINCT and UNION are used daily in real projects

Frequently asked in SQL interviews

Builds strong query-writing confidence

Helps you think like a data engineer

📌 Part of the SQL Job-Ready Series

This is Class 6 of the SQL learning path.
Upcoming classes will cover:
Indexes, Joins Deep Dive, CTEs, Window Functions & Real-World Projects.

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