How to Execute a Query Across All Databases in SQL Server Using a Cursor

Discover how to create a generic SQL query that executes across multiple databases in SQL Server by leveraging cursors for flexibility and efficiency.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Like all databases on the server for a query

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Querying Multiple Databases in SQL Server

When working with SQL Server, it's common to encounter situations where you need to run the same query across all available databases on the server. This can be particularly useful when analyzing permissions or conducting audits. However, dynamically changing the database context in each iteration can be challenging. In this guide, we will explore how to create a SQL query that can run against all databases by utilizing a cursor.

The Challenge

You're faced with a requirement to query all databases to retrieve specific permission information related to the guest user. The initial approach is limited to one database at a time, which makes it necessary to find a solution that allows you to execute the query across all relevant databases.

Here's the basic idea of the task:

You want to run a query that retrieves the database name, user, and permissions for the 'guest' account across multiple databases.

The current query only works for a single database specified by the USE statement.

The Solution: Using Cursors

Cursors in SQL Server allow you to retrieve rows from a result set one at a time. This will enable us to loop through each database and execute our query without the need to manually switch databases. Here’s how to set it up:

Step-by-Step Implementation

Declare Variables: Start by declaring the necessary variables to hold the database name and the command string.

Open and Fetch the Cursor: Open the cursor and fetch the first database into your variable.

Loop Through Databases: Use a WHILE loop to iterate through each database and construct a dynamic SQL command for each one.

Execute the Command: Use sp_executesql to execute the command, allowing you to run the intended query on the selected database.

Example Code

Here's a complete cursor implementation to achieve your goal:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By following the steps outlined above, you can create a flexible and reusable SQL command that allows you to run queries across all databases on your SQL Server. This approach not only simplifies your querying process but also makes it easier to conduct audits and gather information without switching contexts manually for each database.

The use of cursors in SQL Server can be powerful when dealing with multiple results dynamically. Armed with this knowledge, you can now effectively manage database permissions or perform similar analyses across all databases hosted on your SQL Server instance.

Happy querying!