Top SQL Server Interview Questions for Freshers and Experienced Developers
SQL Server interview questions are an integral part of tech interviews. RDBMS is one of the most commonly used database management systems worldwide. Since SQL (Structured Query Language) is the standard language, top tech companies like Google, Amazon, Oracle, Microsoft, etc., ask SQL interview questions in their technical rounds.
To help you ace your SQL Developer interview, this article will provide you with the most frequently asked SQL Server questions in FAANG interviews, as well as everything you need to know.
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SQL interview questions are an important part of technical and coding interviews. In this article, we will go through the top SQL Server interview questions asked to freshers and experienced developers.
We will cover these topics:
- What Do SQL Developers Do?
- Topics to Prepare for Your SQL Server Interview
- Top SQL Server Interview Questions
- How to Prepare for SQL Server Interviews
- FAQs on SQL Server Interview
What Do SQL Developers Do?
SQL Developers design database systems that store and access information related to a business. SQL Developers are responsible for incorporating a high level of technical know-how and data management skills to make the systems safe and secure. Their job is to prevent unauthorized access to these systems as it may put sensitive data and the business’s reputation at risk.
Besides this, SQL Developers are responsible for evaluating network infrastructure and running diagnostic tests. They need to update all information systems to ensure seamless navigation and optimal performance from time to time. To handle sensitive data related to a business, an SQL Developer must possess excellent programming skills, data engineering, and software management skills.
Topics to Prepare for Your SQL Server Interview
The questions asked in SQL interview questions are typically based on the following topics:
- Aggregate functions
- Working with SQL and No-SQL databases
- Nested queries
- Data modeling
- ACID transitions
- Table types
- Start and snow-flake schema
- SQL performance tuning
Top SQL Server Interview Questions
Most SQL Server questions asked in FAANG interviews are based on Relational Database Management Systems (RDBMS). RDBMS is used in companies to retrieve and store data safely and securely. Besides core data handling and data management concepts, SQL Server interview questions are based on the position and required work experience.
SQL Server Interview Questions and Answers
We’ve curated some SQL Server interview questions and answers commonly asked in tech interviews. Practice these questions to increase your chances of nailing the interview.
Q1. An SQL Server runs on which TCP/IP port?
Answer: An SQL Server runs on port 1433 by default.
Q2. Differentiate between non-clustered and clustered indexes.
Answer: A non-clustered index will not rearrange a given table in the order of the index. The leaf nodes consist of index rows and not data pages. One table can have multiple non-clustered indexes.
A clustered index rearranges a given table in the order of the index. The leaf nodes contain data pages as opposed to index rows. There can be only one clustered index.
Q3. Name some index configurations for a table.
Answer: Some index configurations a table can have are:
A table can have one of the following index configurations: No index, clustered index, one clustered index, and multiple non-clustered indexes, multiple non-clustered indexes
Q4. What do you understand about a recovery model?
Answer: A recovery model communicates with the SQL Server about the data that needs to be stored in the transaction log file and its duration. It also communicates about possible backups. Every database has one recovery model alone. The three kinds of recovery models are full, simple, and bulk-logged.
Q5. Name the different backups available in SQL.
Answer: The backups available in an SQL Server are: Full, Differential, Transactional Log, Copy Only, and File and Filegroup.
Q6. Describe a Full Backup.
Answer: One of the most common types of backup in SQL, a full backup makes a complete backup of a database. It will also keep a section of the transaction log for recovery.
Q7. What do you mean by OLTP?
Answer: OLTP stands for Online Transaction Processing. OLTP breaks down complex information into simpler structures using data normalization rules and is used for data integrity.
Q8. What do you understand about RDBMS?
Answer: RDBMS stands for Relational Database Management Systems. It is a database management system that maintains data in tabular form. It is very useful in creating relationships between tables. RDBMS also serves as a powerful tool for data usage as it is used for recombining data items from multiple files.
Q9. List the properties of the Relational tables.
Answer: Here are the main properties of Relational tables:
1. Values are atomic in nature.
2. Column values are similar.
3. Every row is unique.
4. Column sequence is insignificant.
5. Row sequence is insignificant.
6. Each column needs to have a unique name.
Q10. Differentiate between a unique key and a primary key.
Answer: The fundamental differences between a unique key and a primary key are:
The values in the Unique key column identify every row in a table in a unique way. They make a default non-clustered index. Only one NULL is allowed.
The primary key column values identify every row in a table in a unique manner. One cannot reuse Primary key values. A primary key creates a clustered index on the column. This column’s values cannot be null.
Check some Amazon SQL Interview Questions here.
Some More Sample Interview Questions for SQL Developers
- When would you use the UPDATE_STATISTICS command?
- Differentiate between a WHERE CLAUSE and a HAVING CLAUSE.
- What do you understand about Mirroring?
- List the advantages of Mirroring.
- What do you understand about Log Shipping?
- List the advantages of Log shipping.
- Can you make a full database backup in Log Shipping?
- What do you understand about an execution plan?
- Describe Stored Procedure.
- What are the advantages of using Stored Procedures?
- Explain the concept of identity in SQL.
- List some common performance issues in SQL Servers.
- What are the tools available for performance tuning?
- Describe the purpose of a performance monitor?
- In how many ways can you get a count of the number of records in a table?
- Is it possible to rename a column in the output of the SQL query?
- Explain the difference between a Global and a Local temporary table.
- Describe an SQL Profiler.
- Explain authentication modes in an SQL Server.
- How will you check the version of the SQL Server?
Take a look at the top Facebook SQL Interview Questions here.
SQL Server DBA Interview Questions
These are some frequently asked SQL Server DBA interview questions:
- What do you understand by an SQL Server Agent?
- Explain the purpose of a PRIMARY KEY.
- Describe Scheduled Jobs.
- What do you understand by a CHECK Constraint?
- List the different forms of normalization.
SQL Server Interview Questions for Developers
Take a look at these SQL Server interview questions for developers:
- How will you create a table in SQL?
- How will you update an SQL Server database table using SQL?
- Explain a stored procedure.
- Explain the concept of a Trigger and the types of triggers in SQL.
- What is a Subquery?
- Explain Collation.
- Which programming language is supported by the SQL Server?
SQL Server Interview Questions for Candidates With 10 Years of Experience
Here are some advanced SQL Server interview questions for experienced candidates:
- How will you create and execute a user-defined function in SQL?
- Name the TCL Commands available on SQL.
- List the different types of Columns Types Constraints in SQL.
- Are there any advantages of having an index on the SQL Server?
- Describe the function of a database engine in an SQL Server.
- Explain COALESCE in the context of an SQL Server.
- How will you handle exceptions in SQL Server Programming?
- Can you check a lock in a database?
- How will you represent Global temporary tables?
- How will you count the number of records in a table?
- Differentiate between ROLLBACK and COMMIT.
- What is the purpose of @@SPID?
- Where are SQL usernames and passwords stored in an SQL Server?
Recommended Reading: Oracle SQL Interview Questions
FAQs on SQL Server Interview Questions
Q1. What is the salary of an SQL Developer?
The average salary of an SQL Developer is approximately $87,398 per year.
Q2. Are SQL Developer jobs in demand?
According to the 2020 Stack Overflow Developer Survey, SQL is the third most commonly used language by professional developers and coding enthusiasts. Even though the language is 46 years old, it continues to be in high demand among FAANG companies because it is semantically mature, has evolved with time, is open source, secure, extensible, and logically founded.
Q3. Which companies use SQL?
A. Some of the major companies that use SQL are Microsoft, Accenture, Cognizant, NTT Data, Dell, Stack Overflow, and more.
Q4. What are the top skills an SQL Developer should have?
A. If you are considering a career in app development, web development, or other data programming positions, here are some SQL skills that you should work on: Microsoft SQL server skills, Execution, Database management, PHP, SQL Joins, Indexing, Related SQL system, OLAP, Technical SQL data analysis, Managing database architecture, Problem-solving, Critical thinking, Collaborative skills, Precision and detail-oriented skills, Decision-making skills.
Q5. What are the top SQL Server interview questions?
The SQL Server interview questions will differ as per your experience level. Some of the most commonly asked questions are: Describe an SQL Profiler, Name the TCL Commands available on SQL, What are the differences between local and global temporary tables? Can SQL servers be linked to other servers? To get more such SQL Server interview questions, visit Interview Kickstart.
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