title: "if, then, else" in SQLite
body: <p>Without using custom functions, is it possible in SQLite to do the following. I have two tables, which are linked via common id numbers. In the second table, there are two variables. What I would like to do is be able to return a list of results, consisting of: the row id, and NULL if all instances of those two variables (and there may be more than two) are NULL, 1 if they are all 0 and 2 if one or more is 1.</p>
  
  <p>What I have right now is as follows:</p>
  
  <pre><code>
  SELECT 
      a.aid, 
      (SELECT count(*) from W3S19 b WHERE a.aid=b.aid) as num, 
      (SELECT count(*) FROM W3S19 c WHERE a.aid=c.aid AND H110 IS NULL AND H112 IS NULL) as num_null, 
      (SELECT count(*) FROM W3S19 d WHERE a.aid=d.aid AND (H110=1 or H112=1)) AS num_yes 
  FROM W3 a
  </code></pre>
  
  <p>So what this requires is to step through each result as follows (rough Python pseudocode):</p>
  
  <pre><code>
  if row['num_yes'] > 0:
      out[aid] = 2
  elif row['num_null'] == row['num']:
      out[aid] = 'NULL'
  else:
      out[aid] = 1
  </code></pre>
  
  <p>Is there an easier way? Thanks!</p>