Lec-15 || Mastering SQL Set Operations in DBMS - Complete Guide

Mastering SQL Set Operations in DBMS - Complete Guide Introduction Structured Query Language (SQL) is a powerful tool used for managing and manipulating relational databases. One of the essential aspects of SQL is Set Operations, which allow users to combine results from multiple queries efficiently. In this comprehensive guide, we will explore SQL Set Operations in depth, including UNION, UNION ALL, INTERSECT, and MINUS/EXCEPT. Whether you are a beginner or an experienced database professional, this tutorial will equip you with the knowledge and practical insights needed to master SQL Set Operations in DBMS. Understanding SQL Set Operations SQL Set Operations are used to retrieve and combine data from two or more SELECT statements. These operations follow the principles of set theory, which means they manipulate entire sets of data rather than individual records. The four major Set Operations in SQL include: UNION – Combines the results of two queries and removes duplicates. UNION ALL – Combines the results of two queries but retains duplicates. INTERSECT – Returns only the common records between two queries. MINUS (EXCEPT in some databases) – Returns records from the first query that are not present in the second query. Each of these operations has specific use cases and performance considerations, which we will discuss in detail.