SQL Server 2008：计算多个日期范围中的键数

Question

SQL Server 2008再次。我有一个主键pt_id和日期时间列order_dts为每个ID。我想从1996年到2008年每年计算一次密钥的数量，并返回8次结果 - 每年计数一次。对于一个单一的一年

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

的作品，但我我该怎么办所有的年，而不必做一些可笑的像八个不同的查询？

谢谢！

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) 

如果你想这一切在一排，你可以这样做：

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)