sql - Previous Monday & previous Sunday's date based on today's date

Question

I need the correct syntax to give me :

1. Previous week's Monday's date based on the current date/time using GETDATE()
2. Previous week's Sunday's date based on the current date/time using GETDATE()

So, based on today's date (14/09/2012) I would want the following:

1. Previous Monday's date = 03/09/2012
2. Previous Sunday's date = 09/09/2012

Answer 1

Easy:

--start of last week
SELECT DATEADD(wk, DATEDIFF(wk, 6, GETDATE()), 0)

--end of last week
SELECT DATEADD(wk, DATEDIFF(wk, 6, GETDATE()), 6)

EDIT:

The below will handle the Sunday date issue.

DECLARE @input varchar(10)
--SET @input = '9/9/2012' -- simulates a Sunday
SET @input = GETDATE()

--start of last week
SELECT DATEADD(wk, DATEDIFF(wk, 6, 
CASE DATEPART(dw,@input)
WHEN 1 THEN DATEADD(d,-1,@input)
ELSE @input
END
), 0)

--end of last week
SELECT DATEADD(wk, DATEDIFF(wk, 6, 
CASE DATEPART(dw,@input)
WHEN 1 THEN DATEADD(d,-1,@input)
ELSE @input
END
), 6)