datetime and smalldatetime (T-SQL)

Date and time data types for representing date and time of day.

datetime

Date and time data from January 1, 1753, to December 31, 9999, to an accuracy of one three-hundredth second, or 3.33 milliseconds. Values are rounded to increments of .000, .003, or .007 milliseconds, as shown in the table.

 

Example	Rounded example
01/01/98 23:59:59.999	1998-01-02 12:00:00.000
01/01/98 23:59:59.995, 01/01/98 23:59:59.996, 01/01/98 23:59:59.997, or 01/01/98 23:59:59.998	1998-01-01 23:59:59.997
01/01/98 23:59:59.992, 01/01/98 23:59:59.993, 01/01/98 23:59:59.994	1998-01-01 23:59:59.993
01/01/98 23:59:59.990 or 01/01/98 23:59:59.991	1998-01-01 23:59:59.990

SQL Server rejects all values it cannot recognize as dates between 1753 and 9999.

smalldatetime

Date and time data from January 1, 1900, through June 6, 2079, with accuracy to the minute.

Remarks

Values with the datetime data type are stored internally by Microsoft® SQL Server™ 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’s reference date. Values for datetime earlier than January 1, 1753, are not permitted. The other 4 bytes store the time of day represented as the number of milliseconds after midnight.

The smalldatetime data type stores dates and times of day with less precision than datetime. SQL Server 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. Dates range from January 1, 1900, through June 6, 2079, with accuracy to the minute.

See Also