Här, prova detta:
EXEMPELDATA
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);
LÖSNING
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