title: Sqlite , how select data after "case when"
body: <p>here is <code>MyTbl1</code>:</p>
  
  <pre><code>id (integer pk ai)
  name (text char 25)
  phone (int)
  </code></pre>
  
  <p><code>MyTbl2</code>:</p>
  
  <pre><code>v1 (text char25)
  v2 (text char 25)
  </code></pre>
  
  <p>i want make request like a:</p>
  
  <pre><code>select if exists id=1 in MyTbl1 if id=1 exists then select v1 from Mytbl2 if not exists return 0.
  </code></pre>
  
  <p>i try this:</p>
  
  <pre><code>select case when exists(select id from MyTbl1 where id=1) then (select v1 from MyTbl2) else 0 end;
  </code></pre>
  
  <p>its not working( </p>