Solved

select one record of several

Posted on 2011-09-06
3
186 Views
Last Modified: 2012-06-27
I have a table of phone numbers with the following structure:

PersonID, PhoneType, PhoneNumber

Each person can have several phone numbers with different types, and not everybody has the same type.

I am looking for a view which gives me just one phone number, selected by a pre-established order of phonetype. Whenever the view has found this type, it should continue to the next person.

Example:
1000,HOME,1231231110
1000,WORK,1231231111
1000,CELL,1231231112
1001,WORK,1231231113
1002,CELL,1231231114
1002,MESS,1231231115
1003,FAM,1231231116
1004,HOME,1231231117
1004,FAM,1231231118

my selected order is: HOME - WORK - CELL

then the view should contain:

1000,1231231110
1001,1231231113
1002,1231231114
1004,1231231117

How would I write this select statement?

Thanks!
0
Comment
Question by:DerCornet
3 Comments
 
LVL 6

Accepted Solution

by:
markterry earned 500 total points
ID: 36492684
Try this? may not be the prettiest solution, but if you want a view, that should work. I would probably do something with CTE and a procedure if I didnt know what phone types to expect though.
Select 
PersonID, PhoneType, PhoneNumber
from PhoneNumbers
Where PhoneType = 'Home' 
UNION ALL
Select 
PersonID, PhoneType, PhoneNumber
from PhoneNumbers
Where PhoneType = 'Work' 
and PersonID not in
(Select PersonID rom PhoneNumbers Where PhoneType IN ('Home'))
UNION ALL
Select 
PersonID, PhoneType, PhoneNumber
from PhoneNumbers
Where PhoneType = 'Cell'
and PersonID not in
(Select PersonID rom PhoneNumbers Where PhoneType IN ('Home', 'Work'))

Open in new window

0
 
LVL 42

Expert Comment

by:dqmq
ID: 36492689
Select PersonID, PhoneType, PhoneNumber
From
(
Select *, row_number() over(partition by PersonID
 order by  
 case when PhoneType = 'Home' then 1
         when PhoneType = 'Work' then 2
         when PhoneType = 'Cell' then 3
                                               else   4
         end asc
        ) as precedence
 from YourTable) as T1
where T1.precedence = 1

   
0
 

Author Closing Comment

by:DerCornet
ID: 36499429
The solution works fine, but you are right, it doesn't seem to be an elegant solution. I leave the elegant form for another day. I needed a solution now, and that's what it does. (It became a little more involved as I have to look for 7 different phone types ...) And I fear it is a rather slow solution.
0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Question has a verified solution.

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

In this article I will describe the Backup & Restore method as one possible migration process and I will add the extra tasks needed for an upgrade when and where is applied so it will cover all.
Use this article to create a batch file to backup a Microsoft SQL Server database to a Windows folder.  The folder can be on the local hard drive or on a network share.  This batch file will query the SQL server to get the current date & time and wi…
This video shows how to use Hyena, from SystemTools Software, to bulk import 100 user accounts from an external text file. View in 1080p for best video quality.

837 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