Solved

SQL Percentile

Posted on 2008-06-10
6
1,271 Views
Last Modified: 2008-07-03
I have a table with this structure.

Table: Scores
Fields: Date (datetime), Score (int)

I want to get the 70th percentile of Score for each date.

P.S. I will be using VB.NET frontend, Jet backend. (If I'm not mistaken, I cannot use VBA?)
0
Comment
Question by:Thomasian
[X]
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
  • 3
  • 2
6 Comments
 
LVL 53

Expert Comment

by:Dhaest
ID: 21749584
You can get it through this query
Select ID, s1.Date, s1.score
from scores s1 where
s1.Score > (
SELECT Sum(s2.Score)/Count(s2.Date)*70/100
FROM Scores s2
WHERE s1.Date = s2.DAte
GROUP BY s2.Date)
Input:
ID      Date      Score
1      1/11/2008      100
2      1/11/2008      50
3      2/11/2008      75
4      2/11/2008      80
5      2/11/2008      85

Result:
ID      Date      score
1      1/11/2008      100
3      2/11/2008      75
4      2/11/2008      80
5      2/11/2008      85
0
 
LVL 22

Author Comment

by:Thomasian
ID: 21750510
Thanks for the response.

I am expecting to return only one value for each date.

>>Sum(s2.Score)/Count(s2.Date)*70/100
This statement returns the 70% of the average of the scores which I don't think is needed to get the 70th percentile.
0
 
LVL 53

Expert Comment

by:Dhaest
ID: 21750590
What exactly do you need.
The statement I have given will give you all the scores that are over the 70 % of that day
Example
1/11/2008      100
 1/11/2008      50
--> this will give us 100 + 50 points in total for 1/11/2008, which means 150 / 2 = 75 points average.
     if we take take 70 % of this, we get: 56,25 points
     So we return the record 1/11/2008 100 points

it's possible that I misunderstood what you mean with 70th percentile !
0
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 22

Author Comment

by:Thomasian
ID: 21750670
Actually, I want to simulate the percentile function of excel.
http://www.techonthenet.com/excel/formulas/percentile.php
0
 
LVL 53

Accepted Solution

by:
Dhaest earned 400 total points
ID: 21750950
I misunderstood you then :)
Perhaps the following article can set you on your way
Computing Percentiles in SQL Server
http://www.sqlteam.com/article/computing-percentiles-in-sql-server
0
 
LVL 50

Assisted Solution

by:Gustav Brock
Gustav Brock earned 100 total points
ID: 21752265
Read your table into a DataSet, a List, or an array.

Then - some basics here:

http://www.eggheadcafe.com/forumarchives/NETcsharp/Nov2005/post24887990.asp

/gustav
0

Featured Post

Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

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

It’s been over a month into 2017, and there is already a sophisticated Gmail phishing email making it rounds. New techniques and tactics, have given hackers a way to authentically impersonate your contacts.How it Works The attack works by targeti…
You need to know the location of the Office templates folder, so that when you create new templates, they are saved to that location, and thus are available for selection when creating new documents.  The steps to find the Templates folder path are …
Familiarize people with the process of utilizing SQL Server views from within Microsoft Access. Microsoft Access is a very powerful client/server development tool. One of the SQL Server objects that you can interact with from within Microsoft Access…
In Microsoft Access, learn the trick to repeating sub-report headings at the top of each page. The problem with sub-reports and headings: Add a dummy group to the sub report using the expression =1: Set the “Repeat Section” property of the dummy…

749 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