Date and Time (Transact-SQL)
Are data types that are used for representing the date and the time of day.
- datetime and smalldatetime
Represent the date and the time of day.
Data type Range Accuracy
January 1, 1753, through December 31, 9999
January 1, 1900, through June 6, 2079
Values with the datetime data type are stored internally by the SQL Server 2005 Database Engine as two 4-byte integers. The first 4 bytes store the number of days before or after the base date: January 1, 1900. The base date is the system reference date. The other 4 bytes store the time of day represented as the number of 1/300-second units after midnight.
The smalldatetime data type stores dates and times of day with less precision than datetime. The Database Engine stores smalldatetime values as two 2-byte integers. The first 2 bytes store the number of days after January 1, 1900. The other 2 bytes store the number of minutes since midnight.
datetime values are rounded to increments of .000, .003, or .007 seconds, as shown in the following table.
01/01/98 23:59:59.997, or
01/01/98 23:59:59.993, or
01/01/98 23:59:59.990 or
smalldatetime values that are 29.998 seconds or less are rounded down to the nearest minute; values of 29.999 seconds or more are rounded up to the nearest minute.
--Returns time as 12:35. SELECT CAST('2003-05-08 12:35:29.998' AS smalldatetime); GO --Returns time as 12:36. SELECT CAST('2003-05-08 12:35:29.999' AS smalldatetime); GO
ReferenceDate and Time Functions (Transact-SQL)
Data Types (Transact-SQL)
ALTER TABLE (Transact-SQL)
CAST and CONVERT (Transact-SQL)
CREATE TABLE (Transact-SQL)
DECLARE @local_variable (Transact-SQL)
SET @local_variable (Transact-SQL)
Other ResourcesData Type Conversion (Database Engine)
ISO 8601 Format
Alphabetic Date Format
Numeric Date Format
ODBC Datetime Format
Unseparated String Format