Add wp_get_object_terms filters.

[Zatsugami]

I wasted whole day looking for some filter I could use for changing the select query of wp_get_object_terms.

Please add filter like terms_clauses but for wp_get_object_terms (or use the same filter), because terms_clauses is NOT called when there are terms selected for the object. For example. When you select categories for post.

Ok, I've done it myself. It should work.
Basically copy-paste of posts_clauses.
It's somewhere around line 1897 wp-inlcudes/taxonomy.php
Hmm, it may be a stupid question, but can I apply this to be a patch?
If so, how?

$pieces = array( 'select', 'join', 'where', 'orderby', 'order' );

// Setting up initial $query pieces, some are already present
$select = $select_this;
$join 	= "INNER JOIN $wpdb->term_taxonomy AS tt ON tt.term_id = t.term_id INNER JOIN $wpdb->term_relationships AS tr ON tr.term_taxonomy_id = tt.term_taxonomy_id";
$where 	= "WHERE tt.taxonomy IN ($taxonomies) AND tr.object_id IN ($object_ids)";

// We applay filters
$select 	= apply_filters( 'object_terms_select', $select );
$join 		= apply_filters( 'object_terms_join', $join );
$where 		= apply_filters( 'object_terms_where', $where );
$orderby 	= apply_filters( 'object_terms_orderby', $orderby);
$order 		= apply_filters( 'object_terms_order', $order);

// Filter all clauses at once, for convenience
$clauses = (array) apply_filters( 'object_terms_clauses', compact( $pieces ) );
foreach ( $pieces as $piece )
	$$piece = isset( $clauses[ $piece ] ) ? $clauses[ $piece ] : '';
	
$query = "SELECT $select FROM $wpdb->terms AS t $join $where $orderby $order";

$query = apply_filters('object_terms_query', $query);

Replying to Zatsugami:

Hmm, it may be a stupid question, but can I apply this to be a patch?
If so, how?

​http://codex.wordpress.org/Reporting_Bugs#Patching_Bugs

Taxonomy patch. New filters for wp_get_object_terms giving access to select query.

Ok, so are you sure this filter can't be added to a higher-level function?

In my case I needed to join mysql table, so probably there is no other way to do it.
There is posts_clauses, terms_clauses (as I mentioned, it is not called when getting objects terms), but there is no object_terms_clauses or any other filters.

I could use filter 'wp_get_object_terms' which is called at the end of this function, but what you get there is an array of terms, so I would need to loop through them, get the ids of terms and do other query. Anyway, so much unnecessary work would be done.

Also, there would be a small inconsistency in this patch in regards to pieces names in object_terms_clauses array. The 'select' piece in other filters is called 'fields';
But there would be more work to do with the code to make the names the same. But this can be done if you prefer consistency.