EntityFieldQuery and "legacy" nodes

Question

Here's the situation, which I suspect is pretty common:

• A site is deployed where a node type has no fields added.
• Lots of nodes are added.
• The site is changed and a new field is added to the node type.

At this point, I've got my original nodes that do not have a value for the new field. There aren't even any field value records in the database for these nodes.

I now need to query for the nodes where this field is set to a certain value (a new or updated node) OR where it's one of the original nodes. So I'm thinking something like this (note the NULL in my array of possible values):

$query = new EntityFieldQuery();
$query->entityCondition('entity_type', 'node')
  ->entityCondition('bundle', 'my_content_type')
  ->fieldCondition('field_myfield', 'value', array('myvalue', NULL));

Unfortunately, this doesn't work, and I suspect it's due to the nature of the join. Is it possible to return results where the field is a certain value OR where there is no record of a value at all?

ps: how do I see/debug the resulting query?

Answer 1

Although EFQ is a good tool, it starts with the assumption that you are querying about a field value. It does not do the join because it is more efficient to get what you want the way it does it. For you legacy nodes, I think you should do a legacy Dynamic Query. This way you can specify a Left Join to get a result set that includes nodes with NULL/absent entries in the field table.

$query = db_select('node', 'n');
$query->leftJoin('field_data_field_myfield', 'f', 'n.nid = f.entity_id');
$query->condition('f.value', array('myvalue', NULL), 'IN')
  ->condition('n.type', 'my_content_type');

Joins in the dynamic query method.