title: How to find sum of rows based of condition
body: <p>I have following table:</p>
  
  <pre><code>ID Minutes Flag
  -- ------- ---- 
  A    8      0
  A    9      0
  A    21     0
  A    5      0
  B    32     0
  B    21     0
  </code></pre>
  
  <p>and I have to create a table as below  </p>
  
  <pre><code>ID Minutes Flag
  -- ------- ---- 
  A    8      0
  A    9      0
  A    21     1
  A    5      0
  B    32     1
  B    21     0
  </code></pre>
  
  <p>basically I have iterate over given table and update flag when sum of minutes reaches 30 or more and then reset sum(have to find a way to store sum) to 0 and start over again till sum reaches 30 or more </p>
  
  <p>Sum should also reset if ID changes (i.e A to B)</p>
  
  <p>Condition: I have to use SQLite</p>