From: pgsql-sql-ow...@postgresql.org [mailto:pgsql-sql-ow...@postgresql.org] On Behalf Of JORGE MALDONADO Sent: Sunday, September 09, 2012 1:26 PM To: pgsql-sql@postgresql.org Subject: [SQL] Query with LIMIT clause
I have the following records that I get from a query, the fields are date type in day/month/year format: ------------------------------------- Initial Final Date Date ------------------------------------- 27/08/2012 04/09/2012 29/08/2012 09/09/2012 28/08/2012 09/09/2012 30/08/2012 09/09/2012 30/08/2012 09/09/2012 27/08/2012 09/09/2012 31/08/2012 09/09/2012 28/08/2012 10/09/2012 05/09/2012 16/09/2012 As you can see, this result is ordered by Final Date. What I need is to get the last 5 records only. If I use the LIMIT 5 clause I get the first 5. I have tried an ORDEY BY DESC but the result is the same. I will very much appreciate your comments. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>. First, you should really order by both columns, not just "final date". The ties on 9/9/12 are unordered. Second, you will indeed need to reverse the sort order and then take the first 5 records; figuring out and limiting on the last 5 isn't worth the effort. SELECT initial_date, final_date FROM date_source ORDER BY final_date DESC, initial_date DESC LIMIT 5 You can put the above into a sub-query and re-order if the final result is needed in ascending order. If this doesn't seem to work you will want to provide the exact query/queries you are trying so that someone may spot what you are doing wrong. Dave -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
