Differences between smalldatetime and datetime

In SQL Server, smalldatetime can only be accurate to minutes, while datatime can be precise to 3% seconds (3.33 milliseconds ).

Smalldatetime usage4The first two bytes store the base date (January 1, January 1, 1900)AfterThe number of days. The last two bytes are stored after midnightMinutes.

Datetime usage8The first four bytes store the base date (January 1, 1900)BeforeOrAfterThe number of days, the last four bytes are stored after midnightMilliseconds.

Since the precision of datetime is 3% seconds, this involves decimal places. It can be a colon or a decimal point before milliseconds. It indicates the meaning of the colon at the same time, and 11: 11: 11: 21 indicates021Milliseconds. The preceding 0 is omitted, while the decimal point indicates the mathematical decimal point, for example, 11:11:11. 21.210Milliseconds. The value is omitted from the following 0.