Re: select distinct, max, fetch 1 row, something else?

I have a master file supported by a transactions file; the transactions file includes an event code (possibly duplicated) and timestamp.

I'm trying to develop an embedded SQL statement to join the master and transaction files and to return a record set consisting of one row per master record with the master record key, the /last/ event (based on the timestamp), and the /last/ timestamp.

The timestamp is not in the master file, of course.

I have something like this (which provides duplicate records):

select master, event, timestamp from master
left outer join detail on master_key=detail_key
order by master_key,timestamp desc

Here are my problems: DISTINCT appears to work on the whole row and not on a selected columns; and I guess FETCH 1 ROW doesn't work in interactive SQL (or, more likely, /I/ don't know how to use specify "fetch 1 row per order number").

I can solve the problem by eliminating the JOIN and doing a READE against a logical over the transactions file with a descending key on the timestamp; this provides pretty good performance for this interactive application. Or, if I can figure out how to get one record per master/detail record set, I can figure out how to get the last detail.

My SQL thinking is still developing, and I just can't figure out how to tackle this one. I'd appreciate any suggestions!

Thanks,
IRG

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