SQL dateadd (TRANSACT-SQL) returns the time as needed,

 

1. Syntax:

 

 
Dateadd (datepart, number, date)

2. Parameters
 

Datepart

Yes andIntegerThe date part of the Number Addition. The following table lists all valid datepart parameters. The user-defined equivalent variable is invalid.

Datepart	Abbreviations
Year	YY,Yyyy
Quarter	Qq,Q
Month	Mm,M
Dayofyear	Dy,Y
Day	Dd,D
Week	WK,WW
Weekday	DW,W
Hour	HH
Minute	Mi,N
Second	SS,S
Millisecond	MS
Microsecond	MCS
Nanosecond	NS

Number

Is an expression that can be parsed into an int that is added to datepart of date. User-Defined variables are valid.

If you specify a decimal value, the decimal number is truncated without rounding.

Date

Is an expression that can be parsedTime,Date,Smalldatetime,Datetime,Datetime2OrDatetimeoffsetValue. Date can be an expression, column expression, user-defined variable, or string text. If the expression is a string, it must be resolved toDatetimeValue. To avoid uncertainty, use a four-digit year. For information about the two-digit year, see the two digit year cutoff option.

 

 

 

 

3. Example: return the order of the last three months. Consider the specific date.

View code 1 Select * From orderst Where Adddate > Dateadd (m, - 3 , Getdate () Order by adddate

 

 

 

Return the order of the first three months. If the date is not considered, it starts from the first day.

 

CodeAs follows:

View code 1 Select * From orderst Where Datediff (M, adddate, getdate ()) <= 3 Order by adddate

 

 

 

4. display today's order

Select * From orderst where adddate> convert (varchar, getdate (), 112) order by adddate

 

 

 

 

 

 

 

 

1. Refer to: msdn -- dataadd