按天分组和条件计数问题

Question

使用SQLServer 2008r2 - 我有一张表，每小时插入一条记录。我查询的相关列是currentScore（int）和obsDate（smallDateTime）。我希望得到五天的记录。今天，今天的两天（从午夜开始）和未来两天。因此，如果其6月20日我想19年6月18日，20，21和22，我成功地这样做，就像这样：

select dateadd(DAY,0, datediff(day,0, obsDate)) as theDate, 
count(currentScore) as numOfScores 
from diseaseScores 
where siteID=8315 and obsDate > dateAdd(day, -2, (SELECT CONVERT(DATETIME, 
CONVERT(DATE, CURRENT_TIMESTAMP)) + '00:00')) 
group by dateadd(DAY,0, datediff(day,0, obsDate)) 
order by dateadd(DAY,0, datediff(day,0, obsDate)) 

我的记录集看起来像这样：

 theDate   numOfScores 
2017-06-18 00:00:00.000 23 
2017-06-19 00:00:00.000 22 
2017-06-20 00:00:00.000 24 
2017-06-21 00:00:00.000 24 
2017-06-22 00:00:00.000  9 

我想再增加三列，将计算一定范围内的currentScore数量。像这样的东西

CASE 
WHEN currentScore < 8 THEN COUNT(where currentScore < 8) as Low 
WHEN currentScore > 8 and < 17 THEN COUNT(where currentScore > 8 and < 17) as Med 
WHEN currentScore > 17 THEN COUNT(where currentScore > 17) as High 

我可以用select case来做这个吗？达到此目的的最佳方法是什么？

在此先感谢

这里是我想达到的效果：

theDAte numOfScores low med high 
2017-06-18 23  23 0  0 
2017-06-19 22  22 0  0 
2017-06-20 24  5  19 0 
2017-06-21 24  0  24 0 
2017-06-22 9   0  9  0 

Answer 1

首先，使用cast(. . as date)。更清楚！然后，你可以做你想要使用的是什么条件汇总：

select cast(obsDate as date) as theDate, 
     count(currentScore) as numOfScores , 
     sum(case when currentScore < 8 then 1 else 0 end) as currentscore_low, 
     sum(case when currentScore >= 8 and currentScore < 17 then 1 else 0 end) as currentscore_medium, 
     sum(case when currentScore >= 17 then 1 else 0 end) as currentscore_high 
from diseaseScores 
where siteID = 8315 and 
     obsDate >= cast(getdate() - 2 as date) 
group by cast(obsDate as date) 
order by cast(obsDate as date); 

注意：您原来的where子句只有一半的日期条件。我没有补充另一半，但未来两天内应该是非常明显的。