title: how to find first column name with null value in specific row
body: <p>The query below works fine for returning the column names that are null, what I am trying to accomplish is have it return to the first column name with a null value.  I also have another column named email that has a unique email address for each row.  My problem is I cannot figure out the appropriate syntax for doing this.  any help is appreciated!</p>
  
  <p>I am also using php5.2 for this.</p>
  
  <pre><code> SELECT col FROM (SELECT 'GAME0' AS col, GAME0 AS value FROM USERNAME
         UNION ALL SELECT 'GAME1', GAME1 FROM USERNAME
         UNION ALL SELECT 'GAME2', GAME2 FROM USERNAME
         UNION ALL SELECT 'GAME3', GAME3 FROM USERNAME
         UNION ALL SELECT 'GAME4', GAME4 FROM USERNAME
         UNION ALL SELECT 'GAME5', GAME5 FROM USERNAME
         UNION ALL SELECT 'GAME6', GAME6 FROM USERNAME
         UNION ALL SELECT 'GAME7', GAME7 FROM USERNAME
         UNION ALL SELECT 'GAME8', GAME8 FROM USERNAME
         UNION ALL SELECT 'GAME9', GAME9 FROM USERNAME
         UNION ALL SELECT 'GAME10', GAME10 FROM USERNAME
         UNION ALL SELECT 'GAME11', GAME11 FROM USERNAME
         UNION ALL SELECT 'GAME12', GAME12 FROM USERNAME
         UNION ALL SELECT 'GAME13', GAME13 FROM USERNAME
         UNION ALL SELECT 'GAME14', GAME14 FROM USERNAME
         UNION ALL SELECT 'GAME15', GAME15 FROM USERNAME
         UNION ALL SELECT 'GAME16', GAME16 FROM USERNAME
         UNION ALL SELECT 'GAME17', GAME17 FROM USERNAME
         UNION ALL SELECT 'GAME18', GAME18 FROM USERNAME
         UNION ALL SELECT 'GAME19', GAME19 FROM USERNAME
      ) allValues 
      WHERE value is null and email='emailaddress'
  </code></pre>
  
  <p>EDIT:
  if the query above is unneeded, I need something like below, where I can change the value of the first null value.  Again syntax is my biggest problem.</p>
  
  <pre><code>update username
  SET CASE GAME0
      WHEN GAME0 IS NOT NULL THEN GAME1
      WHEN GAME1 IS NOT NULL THEN GAME2
      WHEN GAME2 IS NOT NULL THEN GAME3
      WHEN GAME3 IS NOT NULL THEN GAME4
      WHEN GAME4 IS NOT NULL THEN GAME5
      WHEN GAME5 IS NOT NULL THEN GAME6
      WHEN GAME7 IS NOT NULL THEN GAME8
      WHEN GAME8 IS NOT NULL THEN GAME9
      WHEN GAME9 IS NOT NULL THEN GAME10
      WHEN GAME10 IS NOT NULL THEN GAME11
      WHEN GAME11 IS NOT NULL THEN GAME12
      WHEN GAME12 IS NOT NULL THEN GAME13
      WHEN GAME13 IS NOT NULL THEN GAME14
      WHEN GAME14 IS NOT NULL THEN GAME15
      WHEN GAME15 IS NOT NULL THEN GAME16
      WHEN GAME16 IS NOT NULL THEN GAME17
      WHEN GAME17 IS NOT NULL THEN GAME18
      WHEN GAME18 IS NOT NULL THEN GAME19
    END where EMAIL='emailaddress'
  </code></pre>