Analyze smalldatetime and datetime in SQL

For more information about how to analyze smalldatetime and datetime in SQL, see.

For more information about how to analyze smalldatetime and datetime in SQL, see.

1: Date range

The valid time range of smalldatetime is ~ 2079/6/6
The valid time range of datetime is 1753/1/1 ~ 9999/12/31

2: Accuracy

Smalldatetime is accurate to the minute, while datetime is accurate to 3-bit milliseconds.

3: storage space

Smalldatetime occupies four bytes, and the first two bytes store the number of days after base date (January 1, January 1, 1900. The last two bytes are stored in minutes after midnight.

Datetime occupies 8 bytes. The first 4 bytes store the number of days before or after base date (January 1, 1900), and the last 4 bytes store the number of milliseconds after midnight.

Example	Adjusted example
01/01/98 23:59:59. 999	00:00:00. 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	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	23:59:59. 993
01/01/98 23:59:59. 990 or 01/01/98 23:59:59. 991	23:59:59. 990