SQL Server 2008：計算多個日期范圍內的鍵數

Question

再次使用SQL Server 2008。 我有一個主鍵pt_id和每個ID的datetime列order_dts 。 我想計算1996-2008年每年的密鑰數量，並返回八個結果-每年一次。 一年

SELECT COUNT pm.pt_id AS '1996'
FROM dm.medications pm
WHERE (pm.order_dts BETWEEN '1/1/1996' and '12/31/1996')

可以工作，但是我如何可以多年來不用做像8個不同的查詢這樣荒謬的事情呢？

謝謝！

Answer 1

SELECT COUNT(*),  Year(pm.order_dts) as Year
FROM dm.medications pm
WHERE Year(pm.order_dts) between 1996 AND 2008
group by Year(pm.order_dts)

如果您想一排全部，可以執行以下操作：

SELECT 
    sum(case when Year(pm.order_dts) = 1996 then 1 end) as Count1996,
    sum(case when Year(pm.order_dts) = 1997 then 1 end) as Count1997,
    sum(case when Year(pm.order_dts) = 1998 then 1 end) as Count1998,
    sum(case when Year(pm.order_dts) = 1999 then 1 end) as Count1999,
    sum(case when Year(pm.order_dts) = 2000 then 1 end) as Count2000,
    sum(case when Year(pm.order_dts) = 2001 then 1 end) as Count2001,
    sum(case when Year(pm.order_dts) = 2002 then 1 end) as Count2002,
    sum(case when Year(pm.order_dts) = 2003 then 1 end) as Count2003,
    sum(case when Year(pm.order_dts) = 2004 then 1 end) as Count2004,
    sum(case when Year(pm.order_dts) = 2005 then 1 end) as Count2005,
    sum(case when Year(pm.order_dts) = 2006 then 1 end) as Count2006,
    sum(case when Year(pm.order_dts) = 2007 then 1 end) as Count2007,
    sum(case when Year(pm.order_dts) = 2008 then 1 end) as Count2008
FROM dm.medications pm

Answer 2

select count(pm.pt_id) as count, datepart(yy, pm.order_dts) as year
from dm.medications pm
WHERE (pm.order_dts BETWEEN '1/1/1996' and '12/31/1996')
group by datepart(yy, pm.order_dts)