Index: mollom.install
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/mollom/mollom.install,v
retrieving revision 1.26
diff -u -p -r1.26 mollom.install
--- mollom.install	19 Sep 2010 02:45:46 -0000	1.26
+++ mollom.install	20 Sep 2010 19:47:02 -0000
@@ -503,11 +503,22 @@ function mollom_update_7005() {
   }
 
   // Change {mollom}.quality from varchar into float.
+  // Since some data rows are using an empty string to denote no 'quality'
+  // value, we need to insert a temporary value that is converted to NULL
+  // afterwards.
+  db_update('mollom')
+    ->fields(array('quality' => 9))
+    ->condition('quality', '')
+    ->execute();
   db_change_field('mollom', 'quality', 'quality', array(
     'type' => 'float',
     'size' => 'tiny',
     'not null' => FALSE,
   ));
+  db_update('mollom')
+    ->fields(array('quality' => NULL))
+    ->condition('quality', 9)
+    ->execute();
 
   // Add {mollom}.spam.
   if (!db_field_exists('mollom', 'spam')) {