Dear Devs, welcome to our comprehensive guide on SQL Server DateTime. In this article, we will cover everything you need to know about manipulating dates and times in SQL Server. Whether you are a beginner or an experienced developer, we have got you covered. So, let’s dive in!
Introduction to SQL Server DateTime
SQL Server DateTime is a data type that represents a date and a time value. It is widely used in SQL Server databases for various purposes such as tracking events, storing historical data, and generating reports. DateTime values can be manipulated using a variety of functions and methods provided by SQL Server.
In this section, we will discuss the basics of SQL Server DateTime, including its syntax, range, and precision.
Syntax of SQL Server DateTime
The syntax for DateTime data type in SQL Server is as follows:
Column Name |
Data Type |
|---|---|
date_column |
DateTime |
The above syntax defines a column named “date_column” with the data type “DateTime”. You can use this syntax to create a table with a DateTime column in SQL Server.
Range of SQL Server DateTime
The range of SQL Server DateTime is from January 1, 1753, to December 31, 9999. The minimum value that can be stored in a DateTime column is January 1, 1753, 00:00:00.000, whereas the maximum value is December 31, 9999, 23:59:59.997.
It is important to keep in mind the range of DateTime values while working with SQL Server databases. If you try to insert a value outside the range, you will get an error.
Precision of SQL Server DateTime
The precision of SQL Server DateTime is .00333 seconds, which is equivalent to 3.33 milliseconds. This means that you can store a DateTime value with a precision of up to 3.33 milliseconds.
However, it is important to note that the actual precision of DateTime values may vary depending on the hardware and operating system being used.
Manipulating SQL Server DateTime
Now that we have covered the basics of SQL Server DateTime, let’s move on to manipulating DateTime values. In this section, we will discuss various functions and methods provided by SQL Server for manipulating DateTime values.
GETDATE() Function
GETDATE() is a built-in function in SQL Server that returns the current system date and time. You can use this function to insert the current date and time into a DateTime column in a table.
Here is an example:
INSERT INTO MyTable (date_column) VALUES (GETDATE());
The above query will insert the current date and time into the “date_column” of the “MyTable” table.
DATEADD() Function
DATEADD() is a built-in function in SQL Server that adds a specified value (such as days, months, or years) to a DateTime value. You can use this function to manipulate DateTime values in a variety of ways.
Here is an example:
SELECT DATEADD(day, 7, '2022-05-01') AS NewDate;
The above query will add 7 days to the date ‘2022-05-01’ and return the result as ‘2022-05-08’.
DATEDIFF() Function
DATEDIFF() is a built-in function in SQL Server that returns the difference between two DateTime values in a specified unit of time (such as days, months, or years). You can use this function to calculate the duration between two events.
Here is an example:
SELECT DATEDIFF(year, '1980-01-01', '2022-01-01') AS Age;
The above query will calculate the number of years between ‘1980-01-01’ and ‘2022-01-01′ and return the result as ’42’.
Working with Time Zones in SQL Server DateTime
Working with time zones in SQL Server DateTime can be tricky, especially when dealing with international clients or users. In this section, we will discuss various approaches to handle time zones in SQL Server DateTime.
Using UTC Time Zone
One approach to handling time zones in SQL Server DateTime is to use the Coordinated Universal Time (UTC) time zone. UTC is the standard time zone used by the international community.
You can convert DateTime values to UTC using the GETUTCDATE() function in SQL Server. This function returns the current UTC date and time.
Here is an example:
SELECT GETUTCDATE() AS CurrentUTCDateTime;
The above query will return the current UTC date and time in SQL Server.
Using Application Time Zone
Another approach to handling time zones in SQL Server DateTime is to use the time zone of the application or client. This approach requires storing the time zone information in a separate column in the database.
You can convert DateTime values to the application time zone using the built-in functions and methods provided by your programming language. For example, in C#, you can use the TimeZoneInfo.ConvertTimeFromUtc() method to convert UTC DateTime values to the local time zone.
Working with Dates and Times Separately
Sometimes, you may need to work with dates and times separately in SQL Server. In this section, we will discuss various functions and methods provided by SQL Server for working with dates and times separately.
DATEPART() Function
DATEPART() is a built-in function in SQL Server that extracts a specific part of a DateTime value (such as year, month, or day). You can use this function to retrieve the date or time component of a DateTime value.
Here is an example:
SELECT DATEPART(year, '2022-01-01') AS Year;
The above query will extract the year component from the date ‘2022-01-01’ and return the result as ‘2022’.
CAST() Function
CAST() is a built-in function in SQL Server that converts a DateTime value into a specific data type (such as date, time, or string). You can use this function to work with dates and times separately.
Here is an example:
SELECT CAST('2022-01-01 12:30:45' AS date) AS DateOnly;
The above query will convert the DateTime value ‘2022-01-01 12:30:45’ into a date value and return the result as ‘2022-01-01’.
FAQ
What is the difference between DateTime and DateTime2 in SQL Server?
DateTime2 is an improved version of DateTime in SQL Server that has a larger range (from January 1, 0001, to December 31, 9999) and higher precision (up to 100 nanoseconds). It is recommended to use DateTime2 instead of DateTime for new development in SQL Server.
How can I insert a specific date and time into a DateTime column?
You can insert a specific date and time into a DateTime column using the following syntax:
INSERT INTO MyTable (date_column) VALUES ('2022-01-01 12:30:45');
The above query will insert the date and time ‘2022-01-01 12:30:45’ into the “date_column” of the “MyTable” table.
How can I retrieve records between two specific dates in SQL Server?
You can retrieve records between two specific dates in SQL Server using the following syntax:
SELECT * FROM MyTable WHERE date_column BETWEEN '2022-01-01' AND '2022-01-31';
The above query will retrieve all records from the “MyTable” table where the “date_column” value is between ‘2022-01-01’ and ‘2022-01-31’.
How can I calculate the age of a person in SQL Server?
You can calculate the age of a person in SQL Server using the DATEDIFF() function and specifying the “year” unit of time. Here is an example:
SELECT DATEDIFF(year, '1980-01-01', '2022-01-01') AS Age;
The above query will calculate the number of years between ‘1980-01-01’ and ‘2022-01-01′ and return the result as ’42’.