From: | Joe Conway <mail(at)joeconway(dot)com> |
---|---|
To: | Reg Me Please <regmeplease(at)gmail(dot)com> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Table filter |
Date: | 2007-11-21 19:22:46 |
Message-ID: | 47448586.6050107@joeconway.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
Reg Me Please wrote:
> The meaning is that an entity called by the value of "item" has a number
> of properties called by "property" with value "prop_value".
> So, for a single "item" there can be many different "property" each with its
> own value.
> A filter is a list of property values needed to qualify an entity as
> "good". An entity evaluates as good only when all property values in the
> filter match the ones associated to an item in t_data.
>
> What's missing to me is how to apply a filter to the t_data and get the list
> of the items that evaluate good.
I haven't played with it myself, but it seems to me that you could do
this with an inner join of two crosstabs -- one on t_data and one on the
filters (i.e. you join on the columns of the filter crosstab to the
matching ones in the t_data crosstab).
Joe
From | Date | Subject | |
---|---|---|---|
Next Message | Scott Marlowe | 2007-11-21 19:29:53 | Re: loading a funtion script from a file |
Previous Message | Richard Huxton | 2007-11-21 19:07:02 | Re: loading a funtion script from a file |