SELECT a.Desc,
CASE
WHEN EXISTS(SELECT b.ID2 from TABLE2 b where b.ID1=a.ID1)
THEN 'I EXIST'
ELSE 'I DO NOT THINK I AM HERE'
END
FROM TABLE1 a
WHERE a.ID1 = <keyvalue>

This works,
Set

--- In firebird-support@yahoogroups.com, "Greg At ACD" wrote:
> Hi all,
>
> DB: FB 1.5.2 SuperServer
>
> I have 2 tables as follows (oversimplified for clarity):
>
> Table1:
> ID1 int (this is a PK)
> Desc varchar(80)
>
> Table2:
> ID2 int (this is a PK)
> ID1 int (this is a FK to Table 1)
>
> So, Table1 shares a one to many relationship with Table2.
>
> What I am trying to do is to create a query that, given a valid key
> value, returns "Desc" and an indicator as to whether or not there
> are any instances of ID1 in table 2.
>
> Something like this (obviously pseudo-type code here)
> SELECT a.Desc,
> EXISTS(SELECT b.ID2 from TABLE2 b where b.ID1=a.ID1) AS X
> FROM TABLE1 a
> WHERE a.ID1 = <keyvalue>
>
> I keep thinking there's a way of doing this in a single statement,
> but I cant seem to grab what it might be...
>
> thx!
>
> Greg