I have a table which has repeated entries for the same serial number, and the date for each row. I want to find the latest record for each serial number, and I was talking to a DBA about how to do this. He dictated the following query to me (MS SQL Server):
with latest as ( select ROW_NUMBER() over (partition by DeviceID order by UTCTimestamp desc) grouping, * from Events where EventCode = 0) select * from latest where grouping = 1; Is there a way to write this in Arel? Or should I just use the 'find_by_sql' function in ActiveRecord? My understanding is that the above query creates a temporary table and populates it with the data from the Events. Each row gets an ascending integer depending on its order in the sort and the sequence starts over at 1 every time the DeviceID changes. Then we select just the rows we want from the temporary table. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
