UNION vs UNION ALL in SQL Server | Key Differences Explained скачать в хорошем качестве

UNION vs UNION ALL in SQL Server | Key Differences Explained

In this video, you will learn the difference between UNION and UNION ALL in SQL Server, one of the most frequently asked SQL interview questions. Both operators are used to combine results from multiple SELECT statements, but they behave differently when it comes to duplicate records and performance. We will cover: What is UNION? What is UNION ALL? How duplicates are handled Performance differences Rules for using UNION Real-world examples Interview tips Perfect for beginners, backend developers, and interview preparation. What You Will Learn Syntax of UNION Syntax of UNION ALL Duplicate removal behavior Sorting & execution differences Performance comparison When to use UNION When to use UNION ALL Common mistakes Interview Questions Covered Difference between UNION and UNION ALL Which one is faster? Why is UNION slower? Does UNION sort results? Can we use ORDER BY with UNION? union vs union all sql union tutorial difference between union and union all sql server union sql server union all sql interview questions sql performance comparison sql remove duplicates union all faster than union learn sql server sql tutorial for beginners t sql union backend developer sql database interview questions