In SQL Server 2005, the data type used to store date and time values is datetime. The datetime data type allows you to store both the date and time components in a single column.
Understanding the datetime Data Type
The datetime data type in SQL Server 2005 can store values ranging from January 1, 1753, to December 31, 9999. It has a precision of three-hundredths of a second, which means it can represent time intervals as small as 3.33 milliseconds.
When working with the datetime data type, each value is stored as two integers. The first integer represents the number of days since January 1, 1900, while the second integer represents the number of milliseconds since midnight.
Working with datetime Values
To insert a datetime value into a table column of type datetime, you can use the INSERT INTO statement along with the VALUES clause. For example:
INSERT INTO YourTable (DateTimeColumn) VALUES ('2022-01-01 12:34:56')
You can also retrieve datetime values from a table using SQL queries. To filter datetime values based on specific criteria, you can use comparison operators such as =, >, or <. For example:
SELECT * FROM YourTable WHERE DateTimeColumn > '2022-01-01'
Date and Time Functions in SQL Server 2005
In addition to storing and retrieving datetime values, SQL Server 2005 provides various built-in functions to manipulate and format dates and times.
The GETDATE() function returns the current date and time according to the system clock of the SQL Server. This function is commonly used to insert the current datetime into a table column.
INSERT INTO YourTable (DateTimeColumn) VALUES (GETDATE())
The DATEPART() function allows you to extract specific parts of a datetime value. For example, you can retrieve the year, month, day, hour, minute, or second from a datetime value.
SELECT DATEPART(YEAR, DateTimeColumn) AS Year, DATEPART(MONTH, DateTimeColumn) AS Month, DATEPART(DAY, DateTimeColumn) AS Day FROM YourTable
The CONVERT() function enables you to convert a datetime value from one data type to another. For instance, you can convert a datetime value to a VARCHAR representation with a specific format.
SELECT CONVERT(VARCHAR(10), DateTimeColumn, 103) AS FormattedDate FROM YourTable
In SQL Server 2005, the datetime data type plays an essential role in storing and manipulating date and time values. By understanding how this data type works and utilizing the available date and time functions, you can effectively manage datetime values within your database applications.