title: DB2 case statement for updating a table but multiple columns
body: <p>I am trying to merge 4 separate update statements into one single update statement.
  I have no experience with case statements or if what I'm attempting to do would even work.</p>
  <p>Any input on how to structure this?
  This is my attempt, but it's not working.</p>
  <pre><code>  UPDATE URL
    SET CONTENT_TITLE =
    CASE
       WHEN ID = ? AND SYSTEM_UPDATE_REASON = ? AND CONTENT_TITLE IS NOT NULL AND ? NOT BETWEEN 400 AND 599 OR ID = ? AND SYSTEM_UPDATE_REASON = ? AND CONTENT_TITLE != '' AND ? NOT BETWEEN 400 AND 599 THEN ?
       WHEN ID = ? AND CONTENT_TITLE IS NULL AND ? NOT BETWEEN 400 AND 599 OR ID = ? AND CONTENT_TITLE = '' AND ? NOT BETWEEN 400 AND 599 THEN ?
       WHEN ID = ? AND CONTENT_TITLE IS NOT NULL AND ? BETWEEN 400 AND 599 THEN ?
       WHEN ID = ? AND CONTENT_TITLE IS NULL AND ? BETWEEN 400 AND 599 OR ID = ? AND CONTENT_TITLE = '' AND ? BETWEEN 400 AND 599 THEN ?
    SET CONTENT_DSCR =
    CASE
       WHEN ID = ? AND CONTENT_DSCR IS NULL AND ? NOT BETWEEN 400 AND 599 OR ID = ? AND CONTENT_DSCR = '' AND ? NOT BETWEEN 400 AND 599 THEN ?
       WHEN ID = ? AND CONTENT_TITLE IS NOT NULL AND ? BETWEEN 400 AND 599 THEN ?
    SET SYSTEM_UPDATE_REASON = 'title and dscr update'
    SET UPDATED_ON = SYSDATE
    END
  </code></pre>
  <p>Here are the placeholders (?) I'm using:</p>
  <pre><code>u.urlId, 'title and dscr update', u.statusCode, u.urlId, 'title and dscr update', 
  u.statusCode, u.contentTitle, u.urlId, u.statusCode, u.urlId, u.statusCode, 
  u.contentTitle, u.urlId, u.statusCode, null, null, u.urlId, u.statusCode, u.urlId, 
  u.statusCode, u.contentDescription, u.urlId, u.statusCode, 'title and dscr update'
  </code></pre>