Re: How to limit dropdown list to options based on 'in use' rows from lookup table, for webpage using php and postgresql

On 29/12/2015 16:47, Killian Driscoll wrote:
> Hi,
> I posted my reply to the pgsql-php mailing list but in the meantime I
> got an email to say I was removed from the list: I just joined it so I
> don't know why I was removed....

Hi Killian,

Odd - I'll post this to the list also so others will see it.

> Anyhow, below is the reply I tried to post:
>
> Apologies - 'in use' is my grasping at describing it, and as I guessed
> it was unclear. By 'in use' I mean that from my 50 lookup options for
> county types, to date in the db only 20 country types have been used,
> i.e. my db's countries are of 20 types, e.g. country 1 is type
> 'glorious', country 2 is type 'barren', but no country so far is type
> 'lucky': when one uses the webpage filter I only want the type lookups
> used to date to be seen, i.e. 'glorious' or 'barren', but not 'lucky' as
> the latter would result in a "There are no records to display" message.

Ah, OK, I understand now. I'd imagine a simple inner join between the
two tables should do the trick - you'll get only those rows which exist
in both tables. Something like this:

select [whatever]
from country_table ct
inner join lookup_table lt on (ct.country_type_id = lt.country_type_id)
[etc]

Is this what you need?

Hope the weather's a bit better in Dublin than it is here in Galway -
we're getting lashed by Frank at the moment. :-)

Ray.

--
Raymond O'Donnell :: Galway :: Ireland
rod@iol.ie