Sysdate in SQL Server: Understanding Its Functionality, Syntax and Best Practices

Hello Dev, are you among the many SQL programmers who find themselves frequently needing to work with dates and times? If so, you’re in the right place. In this article, we’ll be discussing one such function—sysdate—that comes in handy when working with dates and times in SQL server. From its syntax and usage to best practices, we’ll cover it all. So without further ado, let’s dive in!

What is sysdate, and How Does it Work?

Sysdate is a date function used in SQL server that returns the current date and time at the time of execution of the SQL command. As such, it’s a very useful function when working with data that is time-sensitive. The syntax for sysdate in SQL server is as follows:

The Four Versions of sysdate and Their Differences

As seen in the syntax above, there are four different versions of the sysdate function that can be used in SQL server. These are:

1. SYSUTCDATETIME(): This version of sysdate returns the current date and time in Coordinated Universal Time (UTC) format. UTC is a standardized time format used globally, and it accounts for time difference due to geographical location. This version is particularly useful when different users are located in different time zones.
2. SYSDATETIMEOFFSET(): This version of sysdate returns the current date and time in datetimeoffset format. This format works the same way as datetime2, but it includes an offset that represents the difference from UTC.
3. SYSDATETIME(): This version of sysdate is like SYSDATETIMEOFFSET() but without the offset. It returns the current date and time in datetime2 format.
4. CURRENT_TIMESTAMP: This version of sysdate returns the current date and time in datetime format, which is the same as GETDATE().

Each of these versions of sysdate has its unique use cases, depending on what you’re trying to achieve with your SQL query. For instance, if you’re working with multiple users located in different time zones, you’d need to use SYSUTCDATETIME() to ensure everyone is on the same time scale.

Sysdate in Action: Examples of Its Usage

Now that we’ve covered what sysdate is and its different versions, let’s take a look at some examples of how it can be used in SQL server:

Example 1: Using sysdate to add a default date value to a column

Sometimes when creating tables, you may want to assign a default date value to a particular column. In such cases, you can use sysdate to achieve this. Here’s an example:

CREATE TABLE my_table (id INT PRIMARY KEY,name VARCHAR(50),date_created DATETIME DEFAULT SYSUTCDATETIME());

This code creates a table called my_table with three columns: id, name, and date_created. We’ve assigned the default value of date_created to be the current date and time in UTC format.

Example 2: Using sysdate to filter records based on date ranges

In some cases, you may want to retrieve records that fall within a particular date range. To achieve this, you can use sysdate in your WHERE clause. Here’s an example:

SELECT *FROM ordersWHERE order_date BETWEEN '2021-01-01' AND SYSDATETIME()

This code retrieves all orders made between January 1st, 2021, and the current date and time.

Example 3: Using sysdate to calculate the age of a record

Another common use for sysdate is in calculating the age of a record. Here’s an example:

SELECT name, DATEDIFF(YEAR, date_created, SYSDATETIME()) AS ageFROM my_table

This code retrieves the name of all records in the my_table table, along with their age (calculated in years) from the date_created column.

Best Practices when Using Sysdate in SQL Server

Now that we know what sysdate is and how it can be used, let’s take a look at some best practices to keep in mind when working with this function in SQL server:

1. Use the right version of sysdate for your use case

Remember, there are four different versions of sysdate in SQL server, and each has its unique use case. Be sure to use the right version that suits your SQL query’s requirements.

2. Be mindful of time zones

When working with users in different time zones, be sure to use the SYSUTCDATETIME() function to ensure everyone is on the same time scale.

3. Avoid using sysdate in your SELECT clause

Although it’s possible to use sysdate in your SELECT clause, it’s generally not recommended as this can lead to performance issues, especially if you’re dealing with large databases.

FAQs

Q1. Can I assign a different date value to sysdate?

No. Sysdate is a built-in function in SQL server that returns the current date and time at the time of execution of the SQL command. It cannot be assigned a different date value.

Q2. Can I use sysdate with other date functions?

Yes, you can use sysdate with other date functions such as DATEDIFF, DATEPART, and DATEADD to perform complex date calculations in SQL server.

Q3. Can sysdate be used in a subquery?

Yes, you can use sysdate in a subquery just like any other SQL function.

So there you have it, Dev. Everything you need to know about sysdate in SQL server. From its function and syntax to best practices, we’ve covered it all. Now go ahead and put this newfound knowledge to good use in your SQL programming!