Search Postgresql Archives

Re: getting the last N tuples of a query

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Jul 8, 2010, at 4:17 PM, Edmundo Robles L. wrote:

> Hi!
> 
> if a want the first   5,10,N tuples  of a query  (even without order)   
> i just  have to do a:
> select  * from table limit 10;

That does not get the first 10 tuples, it merely gets 10 tuples. The database is free to return whichever 10 it can, and in practice, the results will change given enough inserts or deletes.

> So, what is the right way to do that  with no order????


Without an order by clause, there is no concept of "first" or "last". Once you have the order by clause, combine your limit with ascending or descending sorts to get the first or last, respectively.
-- 
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Postgresql Jobs]     [Postgresql Admin]     [Postgresql Performance]     [Linux Clusters]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Postgresql & PHP]     [Yosemite]
  Powered by Linux