Re: Subquery problems

#21

begin Coniglio Sgabbiato schrieb:

Quote:

Another option is to use DISTINCT ON, so something like

SELECT DISTINCT ON (Fld1) Fld3 FROM table ORDER BY Fld1, Fld2 DESC;

But it's rather ugly. As usual, test with your own data to see how its
performance compares with other approaches.

I did not know this clause, good to know, it could be really useful.

Keep in mind, it is a postgresq-extension, not per SQL-spec.

end
Andreas
--
Andreas Kretschmer
Linux - weil ich es mir wert bin!
GnuPG-ID 0x3FFF606C http://wwwkeys.de.pgp.net

#22

begin Coniglio Sgabbiato schrieb:

Quote:

Another option is to use DISTINCT ON, so something like

SELECT DISTINCT ON (Fld1) Fld3 FROM table ORDER BY Fld1, Fld2 DESC;

But it's rather ugly. As usual, test with your own data to see how its
performance compares with other approaches.

I did not know this clause, good to know, it could be really useful.

Keep in mind, it is a postgresq-extension, not per SQL-spec.

end
Andreas
--
Andreas Kretschmer
Linux - weil ich es mir wert bin!
GnuPG-ID 0x3FFF606C http://wwwkeys.de.pgp.net

#23

begin Coniglio Sgabbiato schrieb:

Quote:

Another option is to use DISTINCT ON, so something like

SELECT DISTINCT ON (Fld1) Fld3 FROM table ORDER BY Fld1, Fld2 DESC;

But it's rather ugly. As usual, test with your own data to see how its
performance compares with other approaches.

I did not know this clause, good to know, it could be really useful.

Keep in mind, it is a postgresq-extension, not per SQL-spec.

end
Andreas
--
Andreas Kretschmer
Linux - weil ich es mir wert bin!
GnuPG-ID 0x3FFF606C http://wwwkeys.de.pgp.net

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Re: Subquery problems

comp.databases.postgresql comp.databases.postgresql

Re: Subquery problems - 10-28-2008 , 02:52 AM

Re: Subquery problems - 10-28-2008 , 02:52 AM

Re: Subquery problems - 10-28-2008 , 02:52 AM