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how to select latest or last row in a table

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Join Date: May 2007
Posts: 22
Reputation: markchicobaby is an unknown quantity at this point 
Rep Power: 2
Solved Threads: 0
markchicobaby markchicobaby is offline Offline
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Re: how to select latest or last row in a table

  #8  
Mar 10th, 2008
here's the correct answer that i figured out:
Help with Code Tags 
SELECT cu.cust_name,
            od.order_amount
FROM customers cu, 
         orders od
WHERE cu.cust_id = od.cust_id 
  and od.order_date =
 (select max(order_date) from orders od
        where od.cust_id = cu.cust_id)

That's not a great way to do it, because you've got a subquery. Doing two queries when only one is needed.

You'll find it should perform faster if you do a join and then get the max all in one queery, something like below. It depends on how Oracle optimises it though, performance issues can be fun to play with. In general the following will be better than what you've got above:

Help with Code Tags 
select cu.cust_name, od.order_amount, max(order_date) 
  from customers cu
  join  orders od
    on (cu.cust_id = od.cust_id)
group by cu.cust_name, od.order_amount

Having said that, it really does depend on a number of factors which I won't get into for now.... anyway you have some options now
Last edited by peter_budo : Mar 10th, 2008 at 8:23 pm. Reason: Keep It Organized - please use [code] tags
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