Understanding SQL Server Current Timestamp for Developers

Welcome Dev, are you looking for ways to track data changes in your SQL Server database? SQL Server offers a variety of ways to manage date and time data types. In this article, we’ll delve into one of the most commonly used time-related functions – the SQL Server Current Timestamp. We’ll explore the uses, syntax, and examples of this powerful feature.

What is SQL Server Current Timestamp?

The SQL Server Current Timestamp is a built-in function that returns the current date and time of the SQL Server instance. It’s useful for tracking data changes or for logging user activity by capturing the timestamp of an event.

The Current Timestamp function has a resolution of 3.33 milliseconds and is defined by the operating system of the server. It’s important to keep in mind that the value returned by Current Timestamp is dependent on the time zone setting of the SQL Server instance.

How to Use SQL Server Current Timestamp?

There are two ways to use the SQL Server Current Timestamp function; as a built-in function or as a default value for a column.

Here’s the syntax for using SQL Server Current Timestamp as a built-in function;

Syntax	Description
SELECT CURRENT_TIMESTAMP	Returns the current date and time of the SQL Server instance.

You can also use SQL Server Current Timestamp as a default value for a column. When a new row is inserted into the table, the timestamp of the event will automatically be captured. Here’s the syntax for creating a table with a default value of Current Timestamp;

Syntax	Description
CREATE TABLE table_name ( column_name datetime DEFAULT CURRENT_TIMESTAMP )	Creates a table with a datetime column that defaults to the current timestamp.

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Examples of SQL Server Current Timestamp

Using SQL Server Current Timestamp as a Built-in Function

Let’s see how the SQL Server Current Timestamp function works in practice. Here’s an example that returns the current date and time of the SQL Server instance;

Example	Output
SELECT CURRENT_TIMESTAMP	2022-10-20 12:22:34.973

In this example, the Current Timestamp function returns the date and time to the millisecond precision.

Using SQL Server Current Timestamp as a Default Value

Now let’s see how to use SQL Server Current Timestamp as a default value for a column. Here’s an example that creates a table with a datetime column that defaults to the current timestamp;

Example
CREATE TABLE employee ( id int IDENTITY(1,1), name varchar(50), hire_date datetime DEFAULT CURRENT_TIMESTAMP )

In this example, we create a table named employee with three columns; id, name, and hire_date. The hire_date column has a default value of Current Timestamp.

Now let’s insert some data into the employee table and see how the hire_date column captures the timestamp of the event;

Example
INSERT INTO employee (name) VALUES (‘John’)

When we select data from the employee table, we can see that the hire_date column has captured the timestamp of the insert event;

Example	Output
SELECT * FROM employee	id:1, name:John, hire_date:2022-10-20 12:22:34.973

FAQs

What is the difference between SQL Server Current Timestamp and Getdate()?

Although SQL Server Current Timestamp and Getdate() both return the current date and time, they have different uses. Current Timestamp has a resolution of 3.33 milliseconds and is dependent on the time zone setting of the SQL Server instance. Getdate(), on the other hand, has a higher resolution and is not dependent on the time zone setting.

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Can I change the value returned by SQL Server Current Timestamp?

No, you cannot change the value returned by SQL Server Current Timestamp. The value is defined by the operating system of the server and is not configurable.

What are some use cases for SQL Server Current Timestamp?

SQL Server Current Timestamp is commonly used for tracking data changes or for logging user activity. It’s also useful for creating audit trails, managing expiration dates, and for scheduling tasks in SQL Server Agent.

What is the maximum value for SQL Server Current Timestamp?

The maximum value for SQL Server Current Timestamp is ‘9999-12-31 23:59:59.997’.

How can I convert SQL Server Current Timestamp to a different format?

You can use the Cast or Convert function to convert SQL Server Current Timestamp to a different format. Here’s an example that converts Current Timestamp to a string using the Cast function;

Example	Output
SELECT CAST(CURRENT_TIMESTAMP AS varchar(20))	2022-10-20 12:22:34

Is SQL Server Current Timestamp affected by daylight saving time?

No, SQL Server Current Timestamp is not affected by daylight saving time. The timestamp returned by Current Timestamp is defined by the operating system of the server and remains constant regardless of the time zone or daylight saving time.

We hope this article has helped you understand SQL Server Current Timestamp and how it can be used to manage date and time data types. If you have any questions, please feel free to reach out to us. Happy coding!