Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

SQL: Sub-select, sorting by aggregate review data?

Posted on 2011-03-17
6
572 Views
Last Modified: 2012-05-11
MS SQL:

I have two tables, USERS and REVIEWS

The reviews table contains reviews of the users, with a link on the ID column. A user can have no reviews, or many reviews, the review is a numerical value from 1-5.

I want to perform a SELECT query on the USER table, that will only return users with reviews, and then ORDER them by the users average review value (highest reviewed users first)

Any help?
SELECT DISTINCT  user.ID
 FROM [user]
 RIGHT OUTER JOIN [Review] ON user.ID = review.modelID
 ORDER BY review.ranking DESC

Open in new window

0
Comment
Question by:HADDADD3
  • 3
6 Comments
 
LVL 32

Expert Comment

by:ewangoya
ID: 35159223

SELECT user.ID  
FROM [user]
INNER JOIN       (select ModelID, MAX(ranking) as Ranking
                  from [Review]
                  group by ModelID) RV ON user.ID = RV.ModelID
ranking DESC
0
 
LVL 32

Expert Comment

by:ewangoya
ID: 35159229
sorry

here

SELECT user.ID  , RV.Ranking
FROM [user]
INNER JOIN       (select ModelID, MAX(ranking) as Ranking
                  from [Review]
                  group by ModelID) RV ON user.ID = RV.ModelID
order by Ranking DESC
0
 
LVL 32

Expert Comment

by:ewangoya
ID: 35159239
We can make it cleaner

SELECT [user].ID, RV.Ranking
FROM [user]
INNER JOIN       (select ModelID, MAX(ranking) as Ranking
                  from [Review]
                  group by ModelID) RV ON [user].ID = RV.ModelID
order by Ranking DESC
0
 
LVL 50

Accepted Solution

by:
Lowfatspread earned 500 total points
ID: 35159460
1) inner join
2) group by userid
3) average  
SELECT   user.ID  ,avg(review.ranking) as avg_review,count(*) as Num_reviews
FROM [user] 
inner JOIN [Review] 
ON user.ID = review.modelID
group by user.id
order by 2 desc,3 desc

Open in new window

0

Featured Post

Free learning courses: Active Directory Deep Dive

Get a firm grasp on your IT environment when you learn Active Directory best practices with Veeam! Watch all, or choose any amount, of this three-part webinar series to improve your skills. From the basics to virtualization and backup, we got you covered.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Introduction In my previous article (http://www.experts-exchange.com/Microsoft/Development/MS-SQL-Server/SSIS/A_9150-Loading-XML-Using-SSIS.html) I showed you how the XML Source component can be used to load XML files into a SQL Server database, us…
The Delta outage: 650 cancelled flights, more than 1200 delayed flights, thousands of frustrated customers, tens of millions of dollars in damages – plus untold reputational damage to one of the world’s most trusted airlines. All due to a catastroph…
This video shows, step by step, how to configure Oracle Heterogeneous Services via the Generic Gateway Agent in order to make a connection from an Oracle session and access a remote SQL Server database table.
Using examples as well as descriptions, and references to Books Online, show the different Recovery Models available in SQL Server and explain, as well as show how full, differential and transaction log backups are performed

861 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question