Question

I have a table that allows records to be inserted which are very similar but differ by a single column value or two. For example the following records are in the table:

ID    TITLE                                 URL                             COUNTRY

1494  Hollywood Reporter                    http://www.hollywoodreporter.com    USA
1497  Hollywood Reporter via Drudge Report  http://www.hollywoodreporter.com    NULL
2158  Hollywood Reporter via                http://www.hollywoodreporter.com    NULL

I would like to update the country column in the last two records where the url is the same.
Also I would also like to know how to sort my table by url column so that all duplicate urls are grouped together or even if they are similar as you have in some cases like:

http://www.hollywoodreporter.com       http://www.blog.hollywoodreporter.com

Thanks in advance.

Tried the following and it worked where the urls were the same

UPDATE t1

SET t1.country = t2.country
FROM Sources AS t1
JOIN sources AS t2
ON t1.url = t2.url
WHERE t1.url= t2.url;

just got to figure out the rest. thanks everyone

---

UPDATE

I was able to edit the records that had matching urls but for the ones that are similar like
http://www.pantagraph.com
http://pantagraph.com
http://pantagraph.com/titles

were not updated. When using the sort and select I can view all these records but when trying to update them it does not work. I even just tried this simple version of:

 select * from Sources s
 where s.url like url 

which shows the records but when updating it did not work.

update Sources 
set country = s.country 
from Sources s 
 where s.url like url

Answer 1

You could use a subquery:

update  yt
set     country = (
                  select  distinct country 
                  from    YourTable yt2 
                  where   yt.url = yt2.url 
                          and yt2.country is not null
                  )
from    YourTable yt

This should give an error if there is an URL with different countries: in that case you should adapt the query to choose one of the countries.

Per your comment, to find rows with conflicting countries:

select  url
,       count(distinct country) as NumberOfCountries
from    YourTable
where   country is not null
group by
        url
,       country
having  count(distinct country) > 1