SQL UNION ALL and Set Operators for Data Combining

When working with relational databases, you often need to merge rows from multiple tables into a single, unified dataset. Understanding how to combine query results efficiently is a fundamental skill for anyone working with data. This course teaches you how to use the UNION ALL operator alongside other essential SQL set operations to merge data streams seamlessly, including duplicate handling and performance optimization. You will start by learning core relational database concepts, foundational terminology, and how set operators differ from traditional joins. Next, you will progress to structuring queries, applying aliases, and filtering consolidated results. What you will learn: Understand the difference between UNION, UNION ALL, and other set operators; Combine multiple query results into a single dataset while managing duplicates; Apply column aliases and table prefixes to maintain clean, readable SQL code; Filter consolidated datasets using WHERE and HAVING clauses; Write modern, readable SQL queries using common table expressions (CTEs) for better performance. This text-based course guides you step-by-step from foundational database concepts to writing clear, efficient multi-query combinations. This course is designed for beginners who have a basic familiarity with SQL SELECT statements and want to expand their data-manipulation skills. Start writing more powerful SQL queries to combine and analyze your data today.