Checking existence of data in multiple table in single query

Question

create table x_test1(id number, property varchar2(1000));
insert into x_test1 values (1,'abc');
insert into x_test1 values (2,'ab');
insert into x_test1 values (1,'abcd');
insert into x_test1 values (3,'a');
insert into x_test1 values (4,'b');
insert into x_test1 values (5,'c');
insert into x_test1 values (8,'d');
insert into x_test1 values (10,'e');
create table x_test2(id number, property varchar2(1000));
insert into x_test2 values (1,'abc');
insert into x_test2 values (5,'ab');
insert into x_test2 values (2,'abcd');
insert into x_test2 values (6,'a');
insert into x_test2 values (11,'b');
insert into x_test2 values (15,'c');
insert into x_test2 values (18,'d');
insert into x_test2 values (10,'e');
Given an id I want to check whether its exists in any this tables. However,in acutal sceneraio x_test1, x_test2 contains millions of records so I want to write a SQL query in such way that if we check in x_test1 if it exists there I don;t check in x_test2.
Can I able to write this in one SQL statement ?
Example -
Given id '1' I want to whether its exists in any these two tables
or
Given id '7' I want to whether its exists in any these two tables

Answer 1

Hi,
I loved Michael's solution.
But since he ahs already shown you that, here is another way of doing it.
It may be more expensive since distinct is involved, however it si only to take care of multiple entries in the table.
select
case when 1=(select distinct 1 from x_test1 where id=&x) then
'EXISTS IN TABLE 1'
when 1=(select distinct 1 from x_test2 where id=&x) then
'EXISTS IN TABLE 2'
else
'EXISTS NO WHERE'
end valu
from dualRegards,
Bhushan