[英]SQL | Aggregation
My objective is to get a table such as this: 我的目标是得到一个这样的表:
Request: 请求:
Wards where the annual cost of drugs prescribed exceeds 25 年度处方药费用超过25的病房
ward_no | year | cost
w2 | 2007 | 34
w4 | 2007 | 160
w5 | 2006 | 26
w5 | 2007 | 33
I would input a picture but lack reputation points. 我会输入图片,但缺乏信誉点。
Here is what I have done so far: 到目前为止,这是我所做的:
select w.ward_no,
year(pn.start_date) as year,
pn.quantity * d.price as cost
from ward w,
patient pt,
prescription pn,
drug d
where w.ward_no = pt.ward_no
and
pn.drug_code = d.drug_code
and
pn.patient_id = pt.patient_id
group by w.ward_no,
year,
cost
having cost > 25
order by w.ward_no, year
My current output is such: 我当前的输出是这样的:
ward_no|year|cost
'w2' |2006|0.28
'w2' |2007|3.20
'w2' |2007|9.50
'w2' |2007|21.60
'w3' |2006|10.08
'w3' |2007|4.80
'w4' |2006|4.41
'w4' |2007|101.00
'w4' |2007|58.80
'w5' |2006|25.20
'w5' |2006|0.56
'w5' |2007|20.16
'w5' |2007|12.60
How would I reduce each ward_no to have only a single row of year (say 2006 or 2007) instead of having x of them? 我如何将每个ward_no减少为仅一行(例如2006或2007)而不是x?
Any help would be very much appreciated I am really stuck and have no clue what to do. 任何帮助将不胜感激,我真的很困并且不知道该怎么办。
You are grouping by cost, so each cost gets a new line. 您正在按成本分组,因此每个成本都有一个新行。 Remove the cost from your grouping 从分组中删除费用
select w.ward_no,
year(pn.start_date) as year,
avg(pn.quantity * d.price) as cost
from ward w,
patient pt,
prescription pn,
drug d
where w.ward_no = pt.ward_no
and
pn.drug_code = d.drug_code
and
pn.patient_id = pt.patient_id
group by w.ward_no,
year
having avg(pn.quantity * d.price) > 25
order by w.ward_no, year
You need to group by ward and year, and sum up the costs: 您需要按病房和年份分组,并汇总费用:
select w.ward_no,
year(pn.start_date) as year,
sum(pn.quantity * d.price) as cost
from ward w
inner join patient pt
on pt.ward_no = w.ward_no
inner join prescription pn
on pn.patient_id = pt.patient_id
inner join drug d
on d.drug_code = pn.drug_code
group by w.ward_no,
year(pn.start_date)
having sum(pn.quantity * d.price) > 25
order by w.ward_no, year
What flavor of SQL is this supposed to be for? 这应该用于哪种SQL?
Share and enjoy. 分享并享受。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.