A simplish sqlplus query I'm struggling with!

Question

Can anyone help me with this query
I have two tables
I want to select all the fields from table1 plus one extra variable field (a Boolean) tacked on the end.
The value of the extra field is set dependent on the following condition.
If The value of Field 3 of table1 exists in column 4(field 4) of table2. Then "Y" Else "N"
I think my query needs to look something like this
Select t1.*, Case when con1 then ‘Y’;
     When con2 then ‘N’;
End CASE;
From table1 t1,table2 t2
Where exists(select * from table2 t2 where t2.field4=t1.field3) con1
Thanks

Answer 1

Here is one of the ways.
Select t1.*, 'Y'
From table1 t1,table2 t2
Where exists(select 'X'
               from table2 t2
              where t2.field4=t1.field3)
union all
Select t1.*, 'N'
From table1 t1,table2 t2
Where not exists(select 'X'
                  from table2 t2
                 where t2.field4=t1.field3);