Subject Re: [firebird-support] Re: Subquery Question (FB 1.5)
Author Helen Borrie
At 01:36 AM 8/07/2010, you wrote:
>Here are the two peices of the query I can't get tied together.
>Thanks for looking at it.
>
>select
> watlev.inventory_pk,
> watlev.wl_date,
> watlev.wl_comment
>from
>watlev
>where
>
>/*It is this piece of the SQL Statement I can't seem to puzzle out */
>
> (select
> w.inventory_pk,
> max( w.wl_date ) max_of_wl_date
> from watlev w
> group by w.inventory_pk)

In Fb 2 and above you could use something like that idea by use of derived tables. For Fb 1.5, try the following:

select
w1.inventory_pk,
w1.wl_date,
w1.wl_comment
from
watlev w1
where
w1.wl_date =
(select max( w.wl_date ) from watlev w
where w.inventory_pk = w1.inventory_pk)

Note here I'm discouraging you from mixing table identifiers with table aliases because it becomes illegal in Fb 2+.

./hb