Top 55 SQL Interview Questions and Answers | SQL Technical questions

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Top 55 SQL Interview Questions and Answers | SQL Technical questions
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Looking to ace your next SQL or MySQL interview? This video provides a deep dive into the essential SQL and MySQL topics frequently asked in technical interviews. Whether you're preparing for roles at top tech companies like FAANG or simply looking to enhance your database management skills, this comprehensive guide covers it all.
We start by exploring fundamental SQL concepts such as Joins (INNER, LEFT, RIGHT, and FULL OUTER), Indexes (Clustered and Non-Clustered), and advanced query optimization techniques to speed up your performance. You'll learn how to handle complex SQL queries like finding the Nth highest salary, organization hierarchy queries, and writing efficient subqueries.
The MySQL section dives into database management, from creating, updating, and managing databases to handling data migrations. We also explain how to use MySQL to perform CRUD operations, enforce constraints, and implement transaction controls.
By the end of this video, you'll be able to answer tricky SQL and MySQL interview questions on topics like data normalization, Stored Procedures vs Functions, and Common Table Expressions (CTEs). With real-world examples and step-by-step walkthroughs, this tutorial will boost your confidence for any SQL or MySQL interview.
Subscribe for more SQL and MySQL interview tips, practice problems, and coding tutorials that help you land your dream job in tech!

[@HarithaComputersTechnology]

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[@chethan4160]

Error

[@sandeepbabusirisinagandla2504]

Two outputs with 2 different SQL queries.
(1). When we directly compare lastname = null in WHERE clause, then zero rows return.
(2). When we use COUNT(CASE WHEN lastname is null THEN 1 ELSE 0 END), then the output is 3.
I believe, in the second case, query is count the now of characters.

[@HarithaComputersTechnology]

good! thanks for the comment

[@sandeepbabusirisinagandla2504]

Sir, can you please tell me why I see 3 in the output?

[@AnalyticsPro1]

Good job brother

[@HarithaComputersTechnology]

Thank you so much 😀

[@chethan4160]

We can’t use = too find out null

[@HarithaComputersTechnology]

yes ! if you use = operator, if fetches empty result set