Question

I’ve got two tables in a SQL Server 2000 database joined by a parent child relationship. In the child database, the unique key is made up of the parent id and the datestamp.

I’m needing to do a join on these tables such that only the most recent entry for each child is joined.

Can anyone give me any hints how I can go about this?

Answer 1

Here’s the most optimized way I’ve found to do this. I tested it against several structures and this way had the lowest IO compared to other approaches.

This sample would get the last revision to an article

SELECT t.*
FROM ARTICLES AS t
    --Join the the most recent history entries
        INNER JOIN  REVISION lastHis ON t.ID = lastHis.FK_ID
        --limits to the last history in the WHERE statement
            LEFT JOIN REVISION his2 on lastHis.FK_ID = his2.FK_ID and lastHis.CREATED_TIME < his2.CREATED_TIME
WHERE his2.ID is null