SQL Server datediff function usage

The DATEDIFF () function returns the number of days between two dates.

Syntax

The startdate AND enddate parameters of DATEDIFF (datepart, startdate, enddate) are valid date expressions.

Use the following SELECT statement:

The code is as follows:	Copy code
Select datediff (day, '2017-12-29 ', '2017-12-30') AS DiffDate result: DiffDate 1

Use datediff to obtain the timestamp

The code is as follows:	Copy code
1> SELECT datediff (ss, '2017-01-01 ', GETDATE () as time 2> go Time 1361988498 (1 row affected) 1>

Datediff

Ss indicates in seconds

The timestamp is calculated from this date.

Getdate () current time

The number of seconds between the current read time and is the current timestamp.

Of course, if you can use getdate () to read the current date, you can also use other languages to convert it into a timestamp, such as js and php.

Of course, the datediff function is very powerful, for example, to calculate the number of months between two dates

The code is as follows:	Copy code
1> SELECT datediff (mm, '2017-01-01 ', GETDATE () as time 2> go Time 13 (1 row affected)