One of the common questions that SQL Server users often have is how to list all the columns in a database that are used as identity keys. In this blog post, we will explore a simple query that can help you achieve this.

To begin with, let’s assume we are working with the AdventureWorks database. Here’s the query you can run in the query editor:

USE AdventureWorks;
GO

SELECT SCHEMA_NAME(schema_id) AS schema_name,
       t.name AS table_name,
       c.name AS column_name
FROM sys.tables AS t
JOIN sys.identity_columns c ON t.OBJECT_ID = c.OBJECT_ID
ORDER BY schema_name, table_name;
GO

This query joins the sys.tables and sys.identity_columns system views to retrieve the schema name, table name, and column name for all identity columns in the database. The results are then ordered by schema name and table name.

By running this query, you will get a list of all the columns in the database that are used as identity keys. This information can be useful for various purposes, such as understanding the structure of your database or identifying tables that have auto-incrementing primary keys.

It’s worth mentioning that identity columns are commonly used to generate unique values for primary keys. They automatically increment their value by a specified increment (known as the seed) and can also have a specified maximum value (known as the increment). This makes them ideal for creating surrogate keys or maintaining data integrity.

If you’re interested in learning more about identity columns in SQL Server, here are a few additional blog posts that you might find helpful:

• Jump in Identity Column After Restart
• DELETE, TRUNCATE and RESEED Identity
• Value of Identity Column after TRUNCATE command
• Finding Out Identity Column Without Using Column Name
• Enable Identity Insert – Import Expert Wizard
• @@IDENTITY vs SCOPE_IDENTITY() vs IDENT_CURRENT – Retrieve Last Inserted Identity of Record

Lastly, it’s important to note that while it is not possible to convert an existing column to an identity column in SQL Server, you can add a new auto-incremental identity column to a table after it has been created. This can be achieved using the ALTER TABLE statement. For example:

ALTER TABLE YourTable ADD IDCol INT IDENTITY(1,1);

This script adds a new column named IDCol to the table YourTable with an auto-incremental identity property starting from 1 and incrementing by 1.

That’s all for this blog post! We hope you found this information helpful in understanding identity columns in SQL Server and how to list them in your database. Stay tuned for more SQL Server tips and tricks!