Sequel: Get latest record of multiple

[Florian Aßmann]

Hi there,

first of all I'd like to say that Sequel seems very promising, thank
you Sharon. I'm currently writing a threaded daemon and I can't
figure out how to build this SQL String.

I have an array of category ids which I use to select import records:
db[:imports].filter :category_id => categories.mapid)

Since a category has multiple imports I only want the latest Import
before a Date X for each category. Is this even possible?

Sincerely
Florian

 

[Alin Popa]

Hi there,

first of all I'd like to say that Sequel seems very promising, thank
you Sharon. I'm currently writing a threaded daemon and I can't
figure out how to build this SQL String.

I have an array of category ids which I use to select import records:
db[:imports].filter :category_id => categories.mapid)

Since a category has multiple imports I only want the latest Import
before a Date X for each category. Is this even possible?

Sincerely
Florian

Hi Florian,

I think that you need a field in that table in which you have to put the
timestamp. Maybe this feature that you want is present in some advanced
RDBMS like Oracle/DB2 or maybe Postgresql.

Best regards,

Alin

 

[Florian Aßmann]

Hi Alin,

Am 04.06.2007 um 08:26 schrieb Alin Popa:

first of all I'd like to say that Sequel seems very promising, thank
you Sharon. I'm currently writing a threaded daemon and I can't
figure out how to build this SQL String.

I have an array of category ids which I use to select import records:
db[:imports].filter :category_id => categories.mapid)

Since a category has multiple imports I only want the latest Import
before a Date X for each category. Is this even possible?

Hi Florian,

I think that you need a field in that table in which you have to
put the
timestamp. Maybe this feature that you want is present in some
advanced
RDBMS like Oracle/DB2 or maybe Postgresql.

I defined some methods in my Model that - hopefully - build me up the
query, still needs to be tested though. As the moment I'm having
sequence problems when I try to create Records...

Sincerely
Florian

P.S. I'm using PostgreSQL 8.1