Re: [SQL] Finding the "most recent" rows
От | Brook Milligan |
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Тема | Re: [SQL] Finding the "most recent" rows |
Дата | |
Msg-id | 199904230410.WAA12675@trillium.nmsu.edu обсуждение исходный текст |
Ответ на | Re: [SQL] Finding the "most recent" rows (Chairudin Sentosa <chairudin@prima.net.id>) |
Список | pgsql-sql |
Your script doesn't show how to get the "most recent" rows. True enough, but that's just because of the < 3 condition within the subselect. Take that out and you'll get all the most recent rows (in this example that means largest order_no, but the same works with dates or whatever). What are you trying to show here? The first query was just showing the table, the second the action of the relevant select. I thought this was what you wanted and that you would recognize the effect of the < 3 condition. I just happened to have this example already that illustrated the general idea and expected that you would get the idea. Sorry if I should have been more complete. I think you could just select the highest id, which means the latest data input. In this particular case the id and the order_no column happen to yield the same results (they are both ordered in the same way). That generally won't be the case. But, if you want the highest id within each customer category a simple change to the select below will do it. In any case, to get the largest (or most recent or whatever) anything in each category you need to do a condition involving a subselect with an aggregate. Something like the following will give you the largest (without additional constraint) order_no within each customer. select * from invoices rwhere order_no = (select max (order_no) from invoices r2 where r.customer = r2.customer)order byr.customer, r.order_no; Sorry for the confusion. Cheers, Brook
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