|
|
Posted by Erland Sommarskog on 10/31/07 23:09
(melissa820@hotmail.com) writes:
> I have two tables: one with person information and the other with a
> person's status changes/updates. (A person's status can go from
> Prospective to Current to Completed.)
>
>
>
> Code:
> Person Table:
> UserName FullName
> jsmith Joe Smith
> bjones Bob Jones
> cblack Carol Black
>
> Status Table:
> UserName Status DateChanged
> jsmith Prospective 1/1/2006
> bjones Prospective 1/2/2006
> jsmith Current 3/3/2006
> cblack Prospective 3/3/2006
> bjones Current 4/4/2006
> bjones Completed 5/5/2006
>
>>From the Status Table it's obvious that "bjones" is Completed,
> "cblack" is Prospective, and "jsmith" is Current. But I'm not sure how
> to grab this info from these tables in a select. I'm thinking I might
> need the MAX(DateChanged) in there somewhere, but I have no clue how
> to use it.
>
> Eventually my goal is to say "show me all the names of the people who
> are Current".
Here is a different solution from Roy's and Gert-Jan's. It only runs
on SQL 2005, but it's potentially faster:
WITH numbered AS (
SELECT P.UserName, P.FullName, S.Status,
rowno = row_number() OVER( PARTITION BY P.UserName
ORDER BY S.DateChanged DESC)
FROM Person P
JOIN Status S ON P.UserName = S.UserName
)
SELECT UserName, FullName
FROM numbered
WHERE rowno = 1
AND Status = 'Current'
--
Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se
Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodinfo/previousversions/books.mspx
Navigation:
[Reply to this message]
|