SQL Server

Generate New Guid (uniqueidentifier) in SQL Server2 min read

Welcome to our in-depth guide on generating random unique identifiers in SQL Server using SQL queries. In this article, we will delve into the process of effortlessly creating unique identifiers with the NEWID() function and explore practical examples of incorporating them into your SQL scripts.

Understanding NEWID():

The NEWID() function in SQL Server is designed to produce a new unique identifier (Guid) each time it is called. This feature proves invaluable when working with databases that require distinct identifiers for various purposes.

In this simple example, executing the SQL query SELECT NEWID() will return a newly generated unique identifier, ready for use in your database operations.

Integrating NEWID() with INSERT Statements:

One of the most common use cases for unique identifiers is in populating tables with new records. The process involves seamlessly integrating the NEWID() function into your INSERT statements.

In this example, a new row is added to the ‘Employees’ table, and the unique identifier generated by NEWID() is assigned to the ‘EmployeeID’ column. This ensures that each employee entry has a distinct identifier.

Application in Real-World Scenarios:

The ability to generate random unique identifiers is particularly beneficial in scenarios such as:

  1. Primary Keys: NEWID() is commonly used to generate primary keys for tables, ensuring each record has a unique identifier.
  2. Data Migration: During data migration processes, unique identifiers play a crucial role in maintaining data integrity.
  3. Combining with Other Functions: NEWID() can be combined with other SQL functions to create complex yet unique identifiers tailored to specific requirements.

Best Practices:

When incorporating unique identifiers into your SQL scripts, consider the following best practices:

  1. Efficiency: While NEWID() is efficient for generating unique identifiers, be mindful of its performance impact on large datasets.
  2. Consistency: Ensure consistent usage of unique identifiers across your database schema for clarity and standardization.
  3. Testing: Thoroughly test your SQL scripts in a non-production environment to validate the behavior of the unique identifiers.


Mastering the generation of random unique identifiers in SQL Server is a valuable skill for any database professional. The NEWID() function provides a simple yet powerful tool for creating identifiers that are essential for maintaining data integrity and supporting various database operations. Incorporate these techniques into your SQL scripts, and elevate your database management skills to the next level.

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