问题描述
这是我的桌子
我想获取那些包含ServiceDescription"Plaster"或Skills"Plaster"或在石膏"类别中,并且还希望计算这些供应商的平均价格.
I want to fetch records of Those Vendor which contain ServiceDescription "Plaster" or Skills "Plaster" oris in Category "Plaster" and also want to calculate averagerating of those Vendor.
注意:如果没有任何供应商的评论,那么记录也应该到来.
note:If there is no review Of any vendor then also that records should come.
这是我的查询
select * from UserDetails u
,VendorInCategory v
,CategoryMaster c
,Review rv
where v.CategoryId=c.Id
and u.Id=r.UserId
and u.Id=rv.VendorId
and v.VendorId=u.Id
and ((u.ServiceDescription like '%Plaster%' )
or (u.Skills like '%Plaster%')
or (c.Name like '%Plaster%'))
上面查询中的问题是我没有得到那个没有评论的供应商.
here problem in above query is i am not getting that vendor whose review is not there.
但我还希望该供应商不包含任何评论,但符合我的标准.
but i also want that vendor which does not contain review but matches my criteria.
用户详细信息:
id Servicedescription Skills
1 Plaster plaster
2 construction construvtion
3 plaster plaster
4 null null(not vendor)
5 null null(not vendor)
查看
id CustomerId Vendorid rating
1 4 1 3
2 5 1 3
预期输出:
VendorId ServiceDescription Skills averagerating
1 plaster plaster 3
3 plaster plaster 0
注意:最终输出应按平均评分的降序
Note:final output should in descending order of average rating
推荐答案
在这里,尝试以下操作:
Here, try this:
create table UserDetails(
Id int,
ServiceDescription varchar(20),
Skills varchar(20)
)
create table Review(
Id int,
CustomerId int,
VendorId int,
Rating int
)
insert into UserDetails values(1, 'Plaster', 'plaster'),(2, 'construction', 'construction'),(3, 'plaster', 'plaster');
insert into Review values(1, 4, 1, 3),(2, 5, 1, 3);
解决方案
select
u.Id as VendorId,
u.ServiceDescription,
u.Skills,
isnull(sum(r.rating)/count(r.rating), 0) as AverageRating
from UserDetails u
left join Review r
on r.VendorId = u.id
where
u.ServiceDescription like '%plaster%'
or u.Skills like '%plaster%'
group by
u.Id,
u.ServiceDescription,
u.Skills
order by AverageRating desc
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