Understanding datetime2 in SQL Server

Hello Dev, if you are a database developer and have been using SQL Server, then you must have heard of the datetime2 data type. It’s a high-precision date and time data type introduced in SQL Server 2008. It stores date and time with an accuracy of 100 nanoseconds, compared to the datetime data type that has an accuracy of 3.33 milliseconds.

What is datetime2?

Datetime2 is a data type that allows you to store date and time values with high precision in SQL Server. It supports a range of values from January 1, 0001, to December 31, 9999, with an accuracy of 100 nanoseconds. It’s useful when you need to work with time-related data that requires high precision, such as financial transactions or scientific calculations.

With datetime2, you can store values with different levels of precision, from zero to seven decimal places. The higher the decimal places, the more accurate the data is.

Precision Levels in datetime2

Here are the different levels of precision that you can use with the datetime2 data type:

Precision Level	Number of Decimal Places	Accuracy
0	None	1 day
1	1	100 microseconds
2	2	10 microseconds
3	3	1 microsecond
4	4	100 nanoseconds
5	5	10 nanoseconds
6	6	1 nanosecond
7	7	100 picoseconds

Working with datetime2 in SQL Server

Working with datetime2 data type is just like working with any other data type in SQL Server. You can use it in your CREATE TABLE statements to define columns, or use it in your INSERT and SELECT statements to insert and retrieve values from the database.

Here’s an example of how you can create a table with a datetime2 column:

CREATE TABLE MyTable (ID INT PRIMARY KEY,MyDateTime2Column DATETIME2(3));

In this example, the MyDateTime2Column has a precision level of 3, which means it can store values up to 100 microseconds. You can change the precision level depending on your needs.

Using datetime2 in Functions and Stored Procedures

Datetime2 can also be used in functions and stored procedures just like any other data type. You can define input and output parameters as datetime2, and use them in your queries or calculations.

Example: Using datetime2 in a Stored Procedure

CREATE PROCEDURE MyProc@MyInput datetime2(3),@MyOutput datetime2(3) OUTPUTASBEGINSET @MyOutput = DATEADD(ms, 100, @MyInput);END;

In this example, the stored procedure takes an input parameter of type datetime2 with a precision level of 3, and an output parameter of the same type. It then adds 100 milliseconds to the input value and sets it as the output value using the DATEADD function.

Frequently Asked Questions (FAQ)

What is the difference between datetime and datetime2?

The main difference between datetime and datetime2 is the precision. Datetime has an accuracy of 3.33 milliseconds, while datetime2 has an accuracy of 100 nanoseconds. Datetime2 also supports a wider range of values compared to datetime.

Can datetime2 be used in older versions of SQL Server?

No, datetime2 was introduced in SQL Server 2008, so it’s not available in older versions of SQL Server.

What is the default precision level of datetime2?

The default precision level of datetime2 is 7, which means it can store values up to 100 picoseconds.

Can I convert datetime to datetime2?

Yes, you can convert datetime to datetime2 using the CAST or CONVERT function in SQL Server.

What is the maximum value that can be stored in datetime2?

The maximum value that can be stored in datetime2 is December 31, 9999, at 23:59:59.9999999.

Conclusion

Datetime2 is a powerful data type in SQL Server that allows you to store time values with high precision. It’s useful when you need to perform time-related calculations or store financial or scientific data. With its range of precision levels, you can choose the level of accuracy that best suits your needs.