Mysql CONCAT does not support fields being null

I think the best way and simplest way to solve this problem is to change the database columns to have a default value of an empty string. This way we avoid NULL values.

The easiest way to create NULL values for value2 is to create a date with a To field optional or required, then create a few nodes, then remove the To field, then put the To field back. Then try to use the calendar module.

Because the database column value2 gets created then dropped then created again all nodes will have NULL values for value2.

Since this is all just as simple as editing the field’s settings this could be a very likely scenario while developing a new site without a clear plan, I believe it to be quite serious.

Please not that I have not been able to test my theory yet. I also do not now if there are any repercussions to changing the fields to not allow nulls.

From: (/date/date/date_admin.inc)

/**
 *  Callback for field columns.
 */
function date_columns($field) {
  if ($field['type'] == 'date') {
    $db_columns['value'] = array('type' => 'varchar', 'length' => 20, 'not null' => FALSE, 'sortable' => TRUE);
  }
  
  ...
}

To:

/**
 *  Callback for field columns.
 */
function date_columns($field) {
  if ($field['type'] == 'date') {
    $db_columns['value'] = array('type' => 'varchar', 'length' => 20, 'not null' => TRUE, 'default' => "''", 'sortable' => TRUE);
  }
  
  ...
}