Find previous sunday date algorithm

Question

I found a couple examples online but I don't quite understand how it works. e.g

     SELECT DATEADD(ww, DATEDIFF(ww,0,GETDATE()), 0)

I'm not even sure it does what I want.

What I need is, when the query is executed, it can SELECT * from xTable WHERE xDate is between two dates. Last sunday and next sunday (current week). What could I use to find it automaticly? And please explain because I'm new to SQL.

Answer 1

I looked deeper in trying to understand this query

 SELECT DATEADD(ww, DATEDIFF(ww,0,GETDATE()), 0)

And used it to retreive the previous monday. Now I can simply DATEADD 6 more days to get a full week.

The solution I used :

       Set @Monday =  DATEADD(ww, DATEDIFF(ww,0,GETDATE()), 0)
       Set @Sunday =  DATEADD(dd, 06, @Monday)

Problem solved.