# 50 SQL Server Interview Questions with Answers
## Basic SQL Server Questions
1. **What is SQL Server?**
- SQL Server is a relational database management system (RDBMS) developed by Microsoft that supports transaction processing, business intelligence, and analytics applications.
2. **What are the different editions of SQL Server?**
- Enterprise, Standard, Web, Developer, and Express editions.
3. **What is the difference between clustered and non-clustered indexes?**
- A clustered index determines the physical order of data in a table (only one per table). A non-clustered index is a separate structure that points to the data (multiple allowed per table).
4. **What is a primary key?**
- A primary key is a column or set of columns that uniquely identifies each row in a table and cannot contain NULL values.
5. **What is a foreign key?**
- A foreign key is a column or set of columns that establishes a relationship between data in two tables, enforcing referential integrity.
## Intermediate SQL Server Questions
6. **What is the difference between DELETE, TRUNCATE, and DROP?**
- DELETE removes rows one at a time with logging, TRUNCATE removes all rows quickly without logging individual row deletions, DROP removes the entire table structure.
