SQL Server USER_NAME() Function

SQL Server USER_NAME() Function

The SQL Server USER_NAME() function returns the database user name based on the user ID. This function is useful for retrieving the user name associated with a specific user ID in the SQL Server database.

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Syntax

SELECT USER_NAME([user_id]);

The USER_NAME() function takes a single optional argument:

• user_id: The ID of the user. If omitted, the function returns the name of the current user.

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Example SQL Server USER_NAME() Function Queries

Let's look at some examples of SQL Server USER_NAME() function queries:

1. Basic USER_NAME() Example

SELECT USER_NAME() AS user_name;

This query returns the name of the current user. The result will be:

user_name
----------
username

2. USER_NAME() with Specific User ID

SELECT USER_NAME(1) AS user_name;

This query returns the name of the user with the specified user ID. The result will be:

user_name
----------
dbo

3. USER_NAME() in a Table

CREATE TABLE user_details (
    user_id INT,
    user_name VARCHAR(50)
);
INSERT INTO user_details (user_id, user_name) VALUES (1, USER_NAME(1));
SELECT * FROM user_details;

This example creates a table named user_details and inserts the user name for a specific user ID. The result will be:

user_id  user_name
-------- ----------
1        dbo

4. USER_NAME() with a Variable

DECLARE @user_id INT = 1;
SELECT USER_NAME(@user_id) AS user_name;

This query uses a variable to store a user ID and then retrieves the user name for that ID. The result will be:

user_name
----------
dbo

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Full Example

Let's go through a complete example that includes creating a table, inserting data, and using the USER_NAME() function.

Step 1: Creating a Table

This step involves creating a new table named user_logs to store some sample data with user actions and their corresponding user names.

CREATE TABLE user_logs (
    log_id INT PRIMARY KEY,
    user_id INT,
    user_name VARCHAR(50)
);

In this example, we create a table named user_logs with columns for log_id, user_id, and user_name.

Step 2: Inserting Data into the Table

This step involves inserting some sample data into the user_logs table using the USER_NAME() function to retrieve the user names.

INSERT INTO user_logs (log_id, user_id, user_name) VALUES (1, 1, USER_NAME(1));
INSERT INTO user_logs (log_id, user_id, user_name) VALUES (2, 2, USER_NAME(2));
INSERT INTO user_logs (log_id, user_id, user_name) VALUES (3, 3, USER_NAME(3));

Here, we insert data into the user_logs table.

Step 3: Retrieving User Logs

This step involves selecting the data from the user_logs table to view the user logs along with user names.

SELECT * FROM user_logs;

This query retrieves all the rows from the user_logs table. The result will be:

log_id  user_id  user_name
------  -------  ----------
1       1        dbo
2       2        username2
3       3        username3

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Conclusion

The SQL Server USER_NAME() function is a useful tool for retrieving the database user name based on the user ID. Understanding how to use the USER_NAME() function and its syntax is essential for effective user management and data processing in SQL Server.