如何按周分组？

Question

我需要创建一个报告,我需要按周计算UserHits的总和,从特定年份的第一周到最后一周.

怎么做到这一点？

http://sqlfiddle.com/#!6/eb181/1/0

CREATE TABLE UserData
(
DateCreated dateTime2 NOT NULL,
UserHits int NOT NULL
);

insert into UserData
values
('2014-01-01',100),
('2014-01-02',50),
('2014-01-03',20),
('2014-01-20',100),
('2014-01-21',100),
('2014-01-22',70),
('2014-02-02',100),
('2014-02-03',100);

Answer 1

select  datepart(wk, DateCreated)
,       sum(UserHits)
from    UserData
group by
        datepart(wk, DateCreated)