SQL Service: An Example of addition and subtraction of time (datetime)

Declare @ time int
Select @ time= 20090701
Select @ time = substring (cast (dateadd (day,-1, convert (varchar, @ time, 112) as varchar (20), 7,4) +
Substring (cast (dateadd (day,-1, convert (varchar, @ time, 112) as varchar (20),) +
Substring (cast (dateadd (day,-1, convert (varchar, @ time, 112) as varchar (20)
Print @ time
-- Year, quarter, month, dayofyear, day, week, hour, minute, second, millisecond

@ Time can be varchar or int

Processing of date data format:

Convert (varchar (16), time 1, 20) Result:/* The time is generally the getdate () function or the field in the data table */

Result of convert (varchar (10), time 1, 23): 2007-02-01/* varchar (10) indicates the date output format. If it is not long enough, it will be intercepted */

Statement and query result:
Select convert (varchar (100), getdate (), 0): 05 16 2006 AM
Select convert (varchar (100), getdate (), 1): 05/16/06
Select convert (varchar (100), getdate (), 2): 06.05.16
Select convert (varchar (100), getdate (), 3): 16/05/06
Select convert (varchar (100), getdate (), 4): 16.05.06
Select convert (varchar (100), getdate (), 5): 16-05-06
Select convert (varchar (100), getdate (), 6): 16 05 06
Select convert (varchar (100), getdate (), 7): 05 16, 06
Select convert (varchar (100), getdate (), 8): 10:57:46
Select convert (varchar (100), getdate (), 9): 05 16 2006 10: 57: 46: 827am
Select convert (varchar (100), getdate (), 10): 05-16-06
Select convert (varchar (100), getdate (), 11): 06/05/16
Select convert (varchar (100), getdate (), 12): 060516
Select convert (varchar (100), getdate (), 13): 16 05 2006 10: 57: 46: 937
Select convert (varchar (100), getdate (), 14): 10: 57: 46: 967
Select convert (varchar (100), getdate (), 20): 10:57:47
Select convert (varchar (100), getdate (), 21): 10:57:47. 157
Select convert (varchar (100), getdate (), 22): 05/16/06 10:57:47 AM
Select convert (varchar (100), getdate (), 23 ):
Select convert (varchar (100), getdate (), 24): 10:57:47
Select convert (varchar (100), getdate (), 25): 10:57:47. 250
Select convert (varchar (100), getdate (), 100): 05 16 2006 AM
Select convert (varchar (100), getdate (), 101): 05/16/2006
Select convert (varchar (100), getdate (), 102): 2006.05.16
Select convert (varchar (100), getdate (), 103): 16/05/2006
Select convert (varchar (100), getdate (), 104): 16.05.2006
Select convert (varchar (100), getdate (), 105): 16-05-2006
Select convert (varchar (100), getdate (), 106): 16 05 2006
Select convert (varchar (100), getdate (), 107): 05 16,200 6
Select convert (varchar (100), getdate (), 108): 10:57:49
Select convert (varchar (100), getdate (), 109): 05 16 2006 10: 57: 49: 437am
Select convert (varchar (100), getdate (), 110): 05-16-2006
Select convert (varchar (100), getdate (), 111): 2006/05/16
Select convert (varchar (100), getdate (), 112): 20060516
Select convert (varchar (100), getdate (), 113): 16 05 2006 10: 57: 49: 513
Select convert (varchar (100), getdate (), 114): 10: 57: 49: 547
Select convert (varchar (100), getdate (), 120): 10:57:49
Select convert (varchar (100), getdate (), 121): 10:57:49. 700
Select convert (varchar (100), getdate (), 126): 2006-05-16t10: 57: 49.827
Select convert (varchar (100), getdate (), 130): 18 ???? ?????? 1427 10: 57: 49: 907am
Select convert (varchar (100), getdate (), 131): 18/04/1427 10: 57: 49: 920am

Note:
Use convert:

Convert (data_type [(length)], expression, [style])

Parameters
Expression

Is any valid Microsoft SQL Server expression ..

Data_type

The data types provided by the target system, including bigint and SQL _variant. User-Defined data types cannot be used.
Length

Optional parameters of the nchar, nvarchar, Char, varchar, binary, or varbinary data type.

Style

Date Format style, which converts datetime or smalldatetime data to character data (nchar, nvarchar, Char, varchar, nchar, or nvarchar data type); or string format style, to convert float, real, money, or smallmoney data to character data (nchar, nvarchar, Char, varchar, nchar, or nvarchar data type ).