select DATEADD(month, -1, '2002-09-30 11:35:00')

 


2>
3> select DATEADD(month, -1, '2002-09-30 11:35:00')
4> GO

-----------------------
2002-08-30 11:35:00.000

(1 rows affected)

1.	DATEADD: add or subtract a number of days, months, or years from a specific date
2.	SELECT DATEADD(yy,12,"24 March 1964"): Add 12 years to 24th March 1964
3.	SELECT DATEADD(m,12,"24 March 1964"): Add 12 months to 24th March 1964
4.	SELECT DATEADD(wk,12,"24 March 1964"): Add 12 weeks to 24th March 1964
5.	SELECT DATEADD(hh,12,"24 March 1964"): Add 12 hours to 24th March 1964
6.	Add 12 minutes to 24th March 1964
7.	DATEADD(Day, 90, '4-29-1988'): adds a specific number of date unit intervals to a date/time value
8.	DATEADD(year, 18, '4-29-1988 10:30 AM'): 18 years later
9.	DATEADD(yy, -18, '4-29-1988 10:30 AM'): 18 years before
10.	DATEADD(second, 9000, '4-29-1988 10:30 AM'): 9,000 seconds after
11.	DATEADD(mi, -9000000, '4-29-1988 10:30 AM'): 9,000,000 milliseconds before
12.	SELECT DATEADD(dayofyear, 18, '4-29-1988 10:30 AM')
13.	SELECT DATEADD(quarter, 18, '4-29-1988 10:30 AM')
14.	Combine the CONVERT()and the DATEADD() functions to format a return date value nine months before September 8, 1989
15.	SELECT DATEADD(mi, -30, '2005-09-01 23:30:00.000')
16.	DATEADD: add days to a date
17.	Combine DateADD and DateDIFF to get the last date of a month

select DATEADD(month, -1, '2002-09-30 11:35:00') : DATEADD « Date Timezone « SQL Server / T-SQL