Sqlite , how select data after "case when"

here is MyTbl1:

id (integer pk ai)
name (text char 25)
phone (int)

MyTbl2:

v1 (text char25)
v2 (text char 25)

i want make request like a:

select if exists id=1 in MyTbl1 if id=1 exists then select v1 from Mytbl2 if not exists return 0.

i try this:

select case when exists(select id from MyTbl1 where id=1) then (select v1 from MyTbl2) else 0 end;

its not working(