Top 20 SQL Server Interview Questions and Answers

Yes, I have experience in SQL Server Database Administration.

• I have worked as a SQL Server Database Administrator for 5 years.

• I am proficient in managing and optimizing SQL Server databases.

• I have experience in performance tuning, backup and recovery, and security management.

• I have successfully implemented high availability solutions like AlwaysOn Availability Groups.

• I am familiar with SQL Server Management Studio and other database administration tools.

SQL Server offers various numeric data types for storing different types of numerical values.

• SQL Server provides data types like int, bigint, smallint, tinyint for storing whole numbers.

• Numeric data types like decimal and numeric are used for storing fixed-point numbers.

• Float and real data types are used for storing floating-point numbers with different precision levels.

• Money and smallmoney data types are used for storing monetary values.

There are 4 types of backups available in SQL Server: Full, Differential, Transaction Log, and File/Filegroup.

• Full backup: It backs up the entire database including all data and objects.

• Differential backup: It backs up only the changes made since the last full backup.

• Transaction Log backup: It backs up the transaction log, allowing point-in-time recovery.

• File/Filegroup backup: It backs up individual files or filegroups within a database.

Recovery model in SQL Server determines how transactions are logged and how the database can be restored.

• There are three recovery models in SQL Server: Simple, Full, and Bulk-Logged.

• Simple recovery model automatically truncates the transaction log and only allows restoring to the most recent full or differential backup.

• Full recovery model logs all transactions and allows restoring to a specific point in time using transaction log backups.

• Bulk-Logged recovery model is similar ...read more

SQL is a language used to manage databases, while SQL Server is a Microsoft product that includes a database management system.

• SQL is a language used to interact with databases, while SQL Server is a Microsoft product that includes a database management system.

• SQL can be used with various database management systems like MySQL, Oracle, etc., while SQL Server is specific to Microsoft.

• SQL is a standard language for querying and managing databases, while SQL Server provides addi...read more

Backup in SQL Server is the process of creating a copy of the database to protect against data loss.

• Backups can be full, differential, or transaction log backups.

• Full backups contain all the data in the database.

• Differential backups contain only the data that has changed since the last full backup.

• Transaction log backups capture all the transactions that have occurred since the last transaction log backup.

• Backups are essential for disaster recovery and data protection.

SSRS stands for SQL Server Reporting Services, a server-based reporting platform that allows creating and managing reports.

• SSRS is a part of Microsoft SQL Server.

• It provides a set of tools to create, deploy, and manage reports.

• Reports can be created using various data sources like SQL Server, Oracle, Excel, etc.

• Reports can be exported to various formats like PDF, Excel, Word, etc.

• SSRS also provides a web-based interface to view and manage reports.

Magic Tables are temporary tables created by SQL Server during DML operations.

• Magic Tables are used to access the data before and after a DML operation.

• They are created automatically by SQL Server and cannot be accessed directly.

• They are useful for auditing and logging changes to a table.

• The inserted and deleted tables are examples of Magic Tables.

CTE is a temporary result set that can be referenced within a SELECT, INSERT, UPDATE, or DELETE statement.

• CTE is defined using the WITH keyword followed by a name and a SELECT statement.

• It can be used to simplify complex queries and improve performance.

• CTE can be recursive, allowing a query to reference itself.

• Example: WITH sales AS (SELECT * FROM orders WHERE status = 'completed') SELECT * FROM sales;

• Example: WITH recursive cte AS (SELECT 1 AS n UNION ALL SELECT n+1 FROM cte...read more

SQL Server is a relational database management system, while SQL Server Management Studio is an integrated environment for managing SQL Server databases.

• SQL Server is a relational database management system used for storing and retrieving data.

• SQL Server Management Studio is a graphical user interface tool used for managing SQL Server databases.

• SQL Server is the actual database software, while SQL Server Management Studio is the tool used to interact with and manage the datab...read more

SQL Server performance tuning involves optimizing database design, query optimization, and server configuration.

• Identify and optimize poorly performing queries

• Ensure proper indexing and partitioning

• Monitor server resources and adjust configuration as needed

• Regularly analyze and optimize database design

• Use tools like SQL Profiler and Database Engine Tuning Advisor

• Consider implementing caching and compression techniques

• Regularly review and adjust security settings

• Collaborate wi...read more

Indexing in SQL Server database

• Indexing improves query performance by creating a structure that allows for faster data retrieval

• Clustered and non-clustered indexes are the two types of indexes in SQL Server

• Clustered indexes determine the physical order of data in a table while non-clustered indexes create a separate structure

• Indexing should be done strategically to avoid over-indexing which can slow down data modification operations

The default isolation level in SQL Server is READ COMMITTED. It ensures that each transaction sees only committed data.

• The default isolation level in SQL Server is READ COMMITTED.

• READ COMMITTED ensures that each transaction sees only committed data.

• It provides a balance between concurrency and data consistency.

• Under READ COMMITTED, a transaction can read data that has been modified by another transaction but not yet committed.

• However, it cannot read uncommitted data or data m...read more

SQL Server installation involves several steps to set up the database management system on a server.

• Download the SQL Server installation file from the official Microsoft website.

• Run the installation file and follow the on-screen instructions to set up the server instance.

• Configure server settings such as authentication mode, collation, and data directories.

• Choose the features to install, such as database engine, reporting services, and analysis services.

• Complete the installat...read more

The default port of SQL Server is 1433. Yes, we can change the default port by modifying the SQL Server Configuration Manager.

• The default port for SQL Server is 1433.

• To change the default port, open SQL Server Configuration Manager.

• Navigate to SQL Server Network Configuration and select Protocols for the desired SQL Server instance.

• Right-click on TCP/IP and choose Properties.

• In the IP Addresses tab, scroll down to the IPAll section.

• Change the TCP Port value to the desired por...read more

Setting up Always On group involves configuring multiple SQL Server instances for high availability and disaster recovery.

• Configure Windows Failover Cluster

• Install SQL Server on each node

• Enable Always On Availability Groups feature

• Create availability group and add databases

• Configure listener for client connections

The SQL Server DBA structure includes roles such as junior DBA, senior DBA, and lead DBA.

• Junior DBA: responsible for basic tasks such as backups and restores

• Senior DBA: responsible for performance tuning and troubleshooting

• Lead DBA: responsible for managing the team and making strategic decisions

• Other roles may include database architect and database developer

• The structure may vary depending on the organization's size and needs