Solved

Distinct But Reversed Pairs

Posted on 2009-07-15
4
461 Views
Last Modified: 2012-05-07
I have a table similar to:

colA     colB  colC colD
3          11      ...     ...
54        22
11        3
22        11
22        54

I need only distinct pairs, regardless of the order of the elements of a pair.  That is 3, 11 is a duplicate of 11,3.  I need only one of the two rows. Can be either one.  So the above table should be:

colA     colB
3          11
54        22
22        11

0
Comment
Question by:studioEtc
  • 2
4 Comments
 
LVL 60

Expert Comment

by:chapmandew
ID: 24860047
so, you only care about the values in columna and columnb?
0
 
LVL 37

Expert Comment

by:momi_sabag
ID: 24860061
select distinct cola,colb
from yourTable t1
where not exists (select 1 from yourtable t2 where t1.cola = t2.cola and t1.colb = t2.colb and cola>colb)
0
 

Author Comment

by:studioEtc
ID: 24860566
I didn't think I had any problem with other columns but unfortunately I do.  When there are duplicates, I need to retain the row with the highest value in colC.
0
 
LVL 37

Accepted Solution

by:
momi_sabag earned 500 total points
ID: 24873121
try this

select cola, colb, max(colc)
from  (select case when cola <= colb then cola else colb end as cola,
    case when cola <= colb then colb else cola end as colb, colc
    from yourTable ) t1
group by cola,colb
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

Ever needed a SQL 2008 Database replicated/mirrored/log shipped on another server but you can't take the downtime inflicted by initial snapshot or disconnect while T-logs are restored or mirror applied? You can use SQL Server Initialize from Backup…
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 how to set up a shell script to accept a positional parameter when called, pass that to a SQL script, accept the output from the statement back and then manipulate it in the Shell.
Viewers will learn how to use the INSERT statement to insert data into their tables. It will also introduce the NULL statement, to show them what happens when no value is giving for any given column.

697 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