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SQL Server Interview Questions and Answers

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Based on 530 ratings
see reviews
Shivprasad Koirala

If you are looking forward to crack SQL Server interviews then you are at the right course.

Working in SQL Server and cracking SQL Server interviews are different ball game. Normally SQL Server professionals work on repetitive tasks like back ups , custom reporting and so on. So when they are asked simple questions like  Normalization , types of triggers they FUMBLE.

Its not that they do not know the answer , its just that they need a revision. That's what this course exactly does. Its prepares you for SQL Server interview in 2 days.

Read more

If you are looking forward to crack SQL Server interviews then you are at the right course.

Working in SQL Server and cracking SQL Server interviews are different ball game. Normally SQL Server professionals work on repetitive tasks like back ups , custom reporting and so on. So when they are asked simple questions like  Normalization , types of triggers they FUMBLE.

Its not that they do not know the answer , its just that they need a revision. That's what this course exactly does. Its prepares you for SQL Server interview in 2 days.

Below are the list of questions with answers , demonstration and detailed explanation. Happy learning. Happy job hunting.

Must and Basic Questions on SQL Server - Part 1

  • Question 1  :- Explain normalization ?

  • Question 2  :- How to implement normalization ?

  • Question 3  :- What is denormalization ?

  • Question 4  :- Explain OLTP vs OLAP ?

  • Question 5  :- Explain 1st,2nd and 3rd Normal form ?

  • Question 6  :- Primary Key vs Unique key ?

  • Question 7  :- Differentiate between Char vs Varchar ?

  • Question 8  :- Differentiate between Char vs NChar ?

  • Question 9  :- Whats the size of Char vs NChar ?

  • Question 10 :- What is the use of Index ?

  • Question 11 :- How does it make search faster?

  • Question 12 :- What are the two types of Indexes ?

  • Question 13 :- Clustered vs Non-Clustered index

  • Question 14 :- Function vs Stored Procedures

  • Question 15 :- What are triggers and why do you need it ?

  • Question 16 :- What are types of triggers ?

  • Question 17 :- Differentiate between After trigger vs Instead Of ?

  • Question 18 :- What is need of Identity ?

  • Question 19 :- Explain transactions and how to implement it ?

  • Question 20 :- What are inner joins ?

  • Question 21 :- Explain Left join ?

  • Question 22 :- Explain Right join ?

  • Question 23 :- Explain Full outer joins ?

  • Question 24 :- Explain Cross joins ?

Interview Questions around essential concepts of SQL Server - Part 2

  • Question 25:-Why do we need UNION ?

  • Question 26:-Differentiate between Union vs Union All ?

  • Question 27:-can we have unequal columns in Union?

  • Question 28:-Can column have different data types in Union ?

  • Question 29:- Which Aggregate function have you used ?

  • Question 30:- When to use Group by ?

  • Question 31:- Can we select column which is not part of group by ?

  • Question 32:- What is having clause ?

  • Question 33:- Having clause vs Where clause

  • Question 34:- How can we sort records ?

  • Question 35:- Whats the default sort ?

  • Question 36:- How can we remove duplicates ?

  • Question 37:- Select the first top X records ?

  • Question 38:- How to handle NULLS ?

  • Question 39:- What is use of wild cards ?

  • Question 40:- What is the use of Alias ?

  • Question 41:- How to write a case statement ?

  • Question 42:- What is self reference tables ?

  • Question 43:- What is self join ?

  • Question 44:- Explain the between clause ?

Important questions on SubQuery and Cor-related Queries in SQL-Part 3

  • Question 45:- Explain SubQuery?

  • Question 46:- Can inner Subquery return multiple results?

  • Question 47:- What is Co-related Query?

  • Question 48:- Differentiate between Joins and SubQuery?

  • Question 49:- Performance Joins vs SubQuery?

How to Find Nth Highest Salary ? - Part 4

  • Question 50:- Find NTH Highest Salary in SQL.

Covered Questions on finding Nth highest using co-related & TSQL-Part 5

  • Question 51:-  Select the top nth highest salary using correlated Queries?

  • Question 52:-  Select top nth using using TSQL

  • Question 53:-  Performance comparison of all the methods.

Questions around SQL Server CTE(Common Table Expressions) - Part6

  • Question 54 :- What is CTE ?

  • Question 55 :- Can we execute CTE multiple times ?

  • Question 56 :- What is use of CTE ?

  • Question 57 :- How to write a recursive CTE ?

  • Question 58 :- Can we see some real world examples of CTE ?

  • Question 59 :- Can we perform insert updates on CTE?

  • Question 60 :- Does is update the tables physically ?

  • Question 61 :- What are temporary tables?

  • Question 62 :- Temp tables vs CTE

  • Question 63 :- Performance CTE vs Temp

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What's inside

Learning objectives

  • How to answer basic sql server interview questions around normalization,de-normalization,first/second/third normal forms,oltp and olap.
  • Comparison sql server interview questions around primary key vs unique key,char vs nchar,char vs varchar,clustered vs non-clustered,insteadof vs after triggers
  • Sql query writing questions around inner joins,left joins,right joins,outer joins , cross joins ,union vs union all,subqueries & co-related queries
  • Tricky questions around join vs subquery,group by,having vs where,identity columns,transactions, aggregate functions, sorting and distinct keyword
  • Extensive explanation of tricky questions like select top nth salary,joins vs subquery,self joins,nulls,wild cards,alias & top keyword
  • One complete chapter dedicates to cte(common table expression) which covers definitions,recursive cte,cte scenarios,temp tables vs cte and cte performance
  • Show more
  • Show less

Syllabus

This section covers Normalization,Denormalization,OLTP,OLAP,Primary key,Unique key,Char vs NChar,Char vs Varchar,Indexes,Clustered ,Non-clustered ,Triggers ,Joins:- Left, Right,Outer,Transactions
Read more

In this video we tried to cover important SQL server interview questions -

Question 1  :- Explain normalization ?

Question 2  :- How to implement normalization ?

Question 3  :- What is denormalization ?

Question 4  :- Explain OLTP vs OLAP ?

Question 5  :- Explain 1st,2nd and 3rd Normal form ?

Question 6  :- Primary Key vs Unique key ?

Question 7  :- Differentiate between Char vs Varchar ?

Question 8  :- Differentiate between Char vs NChar ?

Question 9  :- Whats the size of Char vs NChar ?

Question 10 :- What is the use of Index ?

Question 11 :- How does it make search faster?

Question 12 :- What are the two types of Indexes ?

Question 13 :- Clustered vs Non-Clustered index

Question 14 :- Function vs Stored Procedures

Question 15 :- What are triggers and why do you need it ?

Question 16 :- What are types of triggers ?

Question 17 :- Differentiate between After trigger vs Instead Of ?

Question 18 :- What is need of Identity ?

Question 19 :- Explain transactions and how to implement it ?

Question 20 :- What are inner joins ?

Question 21 :- Explain Left join ?

Question 22 :- Explain Right join ?

Question 23 :- Explain Full outer joins ?

Question 24 :- Explain Cross joins ?

This video part covers following questions :-

  • Question 25:-Why do we need UNION ?

  • Question 26:-Differentiate between Union vs Union All ?

  • Question 27:-can we have unequal columns in Union?

  • Question 28:-Can column have different data types in Union ?

  • Question 29:- Which Aggregate function have you used ?

  • Question 30:- When to use Group by ?

  • Question 31:- Can we select column which is not part of group by ?

  • Question 32:- What is having clause ?

  • Question 33:- Having clause vs Where clause

  • Question 34:- How can we sort records ?

  • Question 35:- Whats the default sort ?

  • Question 36:- How can we remove duplicates ?

  • Question 37:- Select the first top X records ?

  • Question 38:- How to handle NULLS ?

  • Question 39:- What is use of wild cards ?

  • Question 40:- What is the use of Alias ?

  • Question 41:- How to write a case statement ?

  • Question 42:- What is self reference tables ?

  • Question 43:- What is self join ?

  • Question 44:- Explain the between clause ?

This video part covers questions around Joins & SubQuery :-

  • Question 45:- Explain SubQuery?

  • Question 46:- Can inner Subquery return multiple results?

  • Question 47:- What is Co-related Query?

  • Question 48:- Differentiate between Joins and SubQuery?

  • Question 49:- Performance Joins vs SubQuery?

This video demonstrates the answer for one of the commonly asked questions on finding nth highest salary in SQL Server using Simple Order by and Top keyword.

In this section we will look in to Nth highest using co-related & TSQL and compare the performances of the same.

Question 54 :- What is CTE ?

Question 55 :- Can we execute CTE multiple times ?

Question 56 :- What is use of CTE ?

Question 57 :- How to write a recursive CTE ?

Question 58 :- Can we see some real world examples of CTE ?

Question 59 :- Can we perform insert updates on CTE?

Question 60 :- Does is update the tables physically ?

Question 61 :- What are temporary tables?

Question 62 :- Temp tables vs CTE

Question 63 :- Performance CTE vs Temp

This the SQL Ebook for Quick revision.

Traffic lights

Read about what's good
what should give you pause
and possible dealbreakers
Prepares learners to answer questions about normalization, OLTP vs OLAP, and types of triggers, which are essential for SQL Server interviews
Explores the differences between clustered and non-clustered indexes, which is a common topic in database administration and development
Reviews the nuances of SQL queries, including joins, subqueries, and correlated queries, which are frequently encountered in SQL Server interviews
Covers common table expressions (CTEs), including recursive CTEs, which are useful for complex data manipulation and are often discussed in interviews
Includes questions about SQL Server features, such as identity columns and transactions, which are important for database design and data integrity
Focuses on SQL Server, so learners should be aware that the content may not be fully applicable to other database systems like MySQL or PostgreSQL

Save this course

Create your own learning path. Save this course to your list so you can find it easily later.
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Reviews summary

Sql interview prep & fundamentals

According to learners, this course is a solid resource for brushing up on fundamental SQL Server concepts frequently encountered in job interviews. Students found the explanations clear and concise, particularly appreciating the coverage of normalization, joins, indexes, and tricky topics like Nth highest salary and CTEs. While primarily a revision tool, many felt it effectively reinforced key knowledge and provided helpful demos. Some newer reviews suggest the course remains relevant, though a few minor points might benefit from updates.
Best suited for those with some prior knowledge.
"It's good for revision, but might be too fast if you're completely new to SQL."
"This course assumes you have some basic SQL knowledge already."
"Think of it as a focused review, not an in-depth learning journey from scratch."
Delivers information directly and efficiently.
"The course is straight to the point, no unnecessary fluff."
"I liked the concise format, it makes it easy to review specific topics."
"Short and sweet lessons focusing just on the interview answers."
Practical demonstrations aid understanding.
"The demonstrations helped solidify my understanding of the concepts."
"Seeing the queries run in the demos was very useful."
"Practical examples make the theory much easier to grasp."
Excellent for refreshing knowledge before interviews.
"Great course for quickly revising key SQL Server concepts before an interview."
"It was a good recap of core topics I needed to brush up on for my interview."
"If you need to refresh SQL knowledge for interviews, this is helpful."
Addresses essential SQL interview questions.
"Covers many of the basic and tricky questions asked in interviews like Nth salary and CTEs."
"The topics covered, like normalization, joins, and indexes, are exactly what I see in interviews."
"Glad it included sections on CTEs and correlated queries, which are important."
Concepts explained simply and effectively.
"The explanations are very clear and to the point."
"Instructor explains complex topics in a very easy way to understand."
"I appreciated how the basic concepts were broken down clearly."
Some content may feel slightly dated.
"While the core concepts are timeless, some examples or references feel a little old."
"A refresh of the content to include newer SQL Server features would be great."
"The information is still relevant, but perhaps could be updated to reflect current practices."

Activities

Be better prepared before your course. Deepen your understanding during and after it. Supplement your coursework and achieve mastery of the topics covered in SQL Server Interview Questions and Answers with these activities:
Review Relational Database Concepts
Solidify your understanding of relational database concepts to better grasp the nuances of SQL Server.
Browse courses on Relational Databases
Show steps
  • Review the definitions of primary keys and foreign keys.
  • Understand the concept of relationships between tables.
  • Familiarize yourself with different types of database models.
Review 'T-SQL Querying'
Deepen your understanding of T-SQL querying techniques by reviewing a comprehensive guide.
View T-SQL Fundamentals (Developer Reference) on Amazon
Show steps
  • Read the chapters related to advanced querying techniques.
  • Take notes on key concepts and best practices.
  • Try out the examples and exercises in a test environment.
Practice SQL Queries on Sample Database
Reinforce your SQL skills by writing and executing queries on a sample SQL Server database.
Show steps
  • Set up a local SQL Server instance or use an online SQL editor.
  • Download and import a sample database like AdventureWorks or Northwind.
  • Practice writing SELECT, INSERT, UPDATE, and DELETE statements.
  • Experiment with different types of JOINs and subqueries.
Four other activities
Expand to see all activities and additional details
Show all seven activities
Review 'SQL Server 2019 Administration Inside Out'
Expand your knowledge of SQL Server administration by reviewing a comprehensive guide.
View SQL Server 2019 Administration Inside Out on Amazon
Show steps
  • Read the chapters related to database administration and security.
  • Take notes on key concepts and best practices.
  • Try out the examples and exercises in a test environment.
Create a Cheat Sheet for SQL Server Syntax
Consolidate your knowledge by creating a cheat sheet of commonly used SQL Server syntax and commands.
Show steps
  • Compile a list of essential SQL Server commands and functions.
  • Organize the cheat sheet by category (e.g., DDL, DML, DCL).
  • Include examples of how to use each command or function.
  • Share your cheat sheet with other students for feedback.
Participate in Mock SQL Interview
Simulate a real interview environment to practice answering SQL Server questions under pressure.
Show steps
  • Find a partner who is also taking the course or preparing for SQL interviews.
  • Take turns asking each other SQL Server interview questions.
  • Provide constructive feedback on each other's answers.
  • Focus on clarity, accuracy, and conciseness.
Design a Database for a Real-World Application
Apply your SQL Server knowledge by designing a database for a real-world application, such as an e-commerce store or a library management system.
Show steps
  • Identify the entities and attributes for your application.
  • Create an entity-relationship diagram (ERD) to visualize the database schema.
  • Implement the database schema in SQL Server using DDL statements.
  • Populate the database with sample data.
  • Write SQL queries to retrieve and manipulate data.

Career center

Learners who complete SQL Server Interview Questions and Answers will develop knowledge and skills that may be useful to these careers:
Database Developer
A database developer designs, develops, and implements databases, including writing stored procedures, triggers, and functions. This course on SQL Server interview questions and answers is directly relevant because of its focus on these topics. For someone looking to work as a database developer this course helps prepare for technical interviews. The course reviews key database principles including normalization, indexes, and transactions. The course also covers common table expressions and other advanced concepts that are relevant to database development tasks.
See salaries and explore the career path for Database Developer
Data Analyst
A data analyst interprets data, analyzes results, and reports them using techniques such as data visualization. A data analyst heavily relies on querying data from databases using SQL. This course provides a strong foundation in SQL Server, focusing on areas such as joins, subqueries, and common table expressions. The course will help data analysts in understanding database structure and how to retrieve specific data efficiently. For someone looking to improve their SQL skills for a data analyst role, this course will be beneficial as it goes into important concepts and queries.
See salaries and explore the career path for Data Analyst
Database Consultant
A database consultant advises organizations on database strategy, performance optimization, and implementation. Often, a database consultant uses SQL in their daily activities. This course on SQL Server interview questions provides a comprehensive look at important concepts such as normalization, indexing, and transaction management. The course may be useful for someone who wishes to enter this area, because it helps prepare for any SQL related questions in technical interviews. The course also covers more advanced topics such as common table expressions.
See salaries and explore the career path for Database Consultant
Data Engineer
A data engineer builds and maintains data pipelines, often interacting with databases to extract, transform, and load data. This role requires a solid foundation in SQL. This course on SQL Server interview questions covers many areas that are relevant in understanding database systems. Topics covered by the course such as indexes, transactions, and common table expressions are all important for data management and data engineering. This course helps data engineers improve their SQL skills.
See salaries and explore the career path for Data Engineer
Reporting Analyst
A reporting analyst creates reports based on data extracted from databases. This includes querying and manipulating data using SQL. This course provides a review of the fundamentals of SQL, including areas such as joins, aggregate functions, and sorting. For a reporting analyst, this course may be useful because it can help with preparing SQL queries required to extract the data for reports. A reporting analyst will also find it valuable to review tricky SQL concepts through this course.
See salaries and explore the career path for Reporting Analyst
Database Administrator
A database administrator is responsible for the performance, integrity, and security of a database. This role involves tasks like database design, implementation, and maintenance, requiring a strong understanding of database concepts. This course, focusing on SQL Server interview questions, may help those preparing for technical interviews in the field. The course's coverage of normalization, indexing, and transaction management helps build a foundation for daily tasks. The course also presents common interview questions about triggers, joins, and stored procedures which are used by database administrators. This course helps someone who wishes to enter the field review essential topics.
See salaries and explore the career path for Database Administrator
Business Intelligence Analyst
A business intelligence analyst leverages data to understand business performance and inform decisions. They use SQL to extract information from databases. This course on SQL Server provides a chance to review essential SQL concepts with its focus on joins, subqueries, and aggregate functions. By learning how to retrieve and manipulate data, the course helps someone in this role to get the data they need for their analysis. This course may be useful for those who want to ensure they have SQL expertise.
See salaries and explore the career path for Business Intelligence Analyst
Data Scientist
A data scientist uses data to perform statistical analysis and create predictive models, often querying data from various databases. This course in SQL Server helps data scientists build a foundation in querying data with its coverage of joins, subqueries, and aggregate functions. This course may be useful for data scientists who want to practice SQL queries. They might find this helpful in performing their daily duties. The course will help them to understand database structure and how to retrieve specific data efficiently.
See salaries and explore the career path for Data Scientist
Solutions Architect
A solutions architect designs technical solutions, often involving databases. This course focusing on SQL Server may provide useful background for a solutions architect who works with technology requiring databases. By reviewing SQL concepts, the course will give them a better understanding of database principles and how to best use them. A solutions architect may find that this course helps in the technical design of software systems that store data. The course addresses important aspects of databases including joins, subqueries, and common table expressions.
See salaries and explore the career path for Solutions Architect
Information Architect
An information architect structures and organizes information systems. This includes databases, often requiring an understanding of SQL. This course on SQL Server provides a chance to review database concepts such as normalization, data types, and indexing. The course also discusses query writing skills with topics such as joins and subqueries. An information architect may find this course useful as a way to familiarize themselves with SQL. This helps them better understand database structure and capabilities.
See salaries and explore the career path for Information Architect
Software Developer
A software developer often needs to interact with databases in their daily work, in order to store and retrieve data. The software developer may use SQL. This course provides a review of database concepts, like normalization and indexing. It also goes into queries, such as joins and subqueries. This will be helpful to a software developer who is trying to learn or practice SQL. This course may be useful in the application development portion of a software developer's role.
See salaries and explore the career path for Software Developer
System Analyst
A system analyst evaluates and optimizes existing systems. This may involve understanding the underlying data structure and SQL queries. This course focusing on SQL Server interview questions and answers may be useful for any system analyst who needs to work with databases. The course reviews relational database concepts including normalization and indexing. It also covers how to write important queries with topics such as joins and subqueries. These SQL skills are helpful for a system analyst, and this course may be useful to brush up on them.
See salaries and explore the career path for System Analyst
Quality Assurance Analyst
A quality assurance analyst tests software and systems, which may involve validating data in databases. They may need to write SQL queries to verify data integrity. This course on SQL Server could be useful for a quality assurance analyst in learning SQL queries. The course teaches about joins, subqueries, and aggregate functions, which are all important for data validation. This course may be useful for someone looking to enhance their SQL skills in order to test software applications.
See salaries and explore the career path for Quality Assurance Analyst
Technical Support Specialist
A technical support specialist often encounters database related issues. This course focusing on SQL Server may help a technical support specialist better troubleshoot problems. The course's focus on SQL Server concepts, such as transactions, indexes, and query writing can help in diagnosing database problems. This review of SQL may be useful for any technical support professional.
See salaries and explore the career path for Technical Support Specialist
Technical Trainer
A technical trainer develops and delivers training programs on various technical topics, potentially including SQL Server. This course on SQL Server interview questions and answers may be useful for technical trainers. The course reviews important SQL topics, including database design concepts and writing queries, which are commonly asked about during technical interviews. This course may be helpful for a technical trainer as they develop materials and improve their knowledge of SQL.
See salaries and explore the career path for Technical Trainer

Reading list

We've selected two books that we think will supplement your learning. Use these to develop background knowledge, enrich your coursework, and gain a deeper understanding of the topics covered in SQL Server Interview Questions and Answers.
Cover image
T-SQL Fundamentals
Save
Deep dive into T-SQL querying techniques. It covers advanced topics such as window functions, pivoting, and optimization. It is particularly useful for those who want to master the art of writing efficient and effective SQL queries. This book adds depth to the course by providing advanced querying knowledge.
T-SQL Fundamentals (Developer Reference)
Paperback
$$
T-SQL Fundamentals (Developer Reference)
Paperback
$$
Microsoft SQL Server 2012 T-SQL Fundamentals
Paperback
$$
Microsoft SQL Server 2012 T-SQL Fundamentals...
Kindle Edition
$$
Microsoft SQL Server 2012 T-SQL Fundamentals by...
Unknown Binding
$$$
Cover image
SQL Server 2019 Administration Inside Out
Save
Provides a comprehensive guide to administering SQL Server 2019. It covers topics such as installation, configuration, security, and performance tuning. It useful reference for understanding the practical aspects of managing SQL Server environments. This book adds breadth to the course by providing real-world administration knowledge.
SQL Server 2019 Administration Inside Out
Paperback
$$$
SQL Server 2019 Administration Inside Out
Kindle Edition
$$

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Effort
2.5 total hours
Via
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Instructor
Shivprasad Koirala
Language
English
Traffic lights
Read about what's good
what should give you pause
and possible dealbreakers
Prepares learners to answer questions about normalization, OLTP vs OLAP, and types of triggers, which are essential for SQL Server interviews
Explores the differences between clustered and non-clustered indexes, which is a common topic in database administration and development
Reviews the nuances of SQL queries, including joins, subqueries, and correlated queries, which are frequently encountered in SQL Server interviews
Covers common table expressions (CTEs), including recursive CTEs, which are useful for complex data manipulation and are often discussed in interviews
Includes questions about SQL Server features, such as identity columns and transactions, which are important for database design and data integrity
Focuses on SQL Server, so learners should be aware that the content may not be fully applicable to other database systems like MySQL or PostgreSQL
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