fetch( 'content', 'tree', hash( 
'parent_node_id', 63,
'class_filter_type', 'include',
'class_filter_array',array( 'pc_article' ),
'main_node_only', true(),
'sort_by', array( 'attribute', false(), 'pc_article/publish_date' ),
'limit', 5 ) )}

SELECT DISTINCT ezcontentobject.contentclass_id
FROM ezcontentobject_tree 
INNER JOIN ezcontentobject ON (ezcontentobject_tree.contentobject_id = ezcontentobject.id) 
INNER JOIN ezcontentclass ON (ezcontentclass.version = 0 AND ezcontentclass.id = ezcontentobject.contentclass_id) 
INNER JOIN ezcontentobject_attribute a0 ON ( a0.contentobject_id = ezcontentobject.id AND a0.contentclassattribute_id=747 
AND a0.version=ezcontentobject.current_version )
WHERE ezcontentobject_tree.path_string like '/1/2/60/63/%' 
AND ezcontentobject_tree.node_id != 63 
AND ezcontentobject_tree.node_id = ezcontentobject_tree.main_node_id 
AND ezcontentobject.contentclass_id IN ( 17 ) 
AND ezcontentobject.language_mask & 3 > 0 
ORDER BY a0.sort_key_int DESC LIMIT 0, 5;

SELECT DISTINCT ezcontentobject.contentclass_id, 
                ezcontentobject.current_version, 
                ezcontentobject.id, 
                ezcontentobject.initial_language_id, 
                ezcontentobject.language_mask, 
                ezcontentobject.modified, 
                ezcontentobject.owner_id, 
                ezcontentobject.published, 
                ezcontentobject.remote_id           AS object_remote_id, 
                ezcontentobject.section_id, 
                ezcontentobject.status, 
                ezcontentobject_tree.contentobject_is_published, 
                ezcontentobject_tree.contentobject_version, 
                ezcontentobject_tree.depth, 
                ezcontentobject_tree.is_hidden, 
                ezcontentobject_tree.is_invisible, 
                ezcontentobject_tree.main_node_id, 
                ezcontentobject_tree.modified_subnode, 
                ezcontentobject_tree.node_id, 
                ezcontentobject_tree.parent_node_id, 
                ezcontentobject_tree.path_identification_string, 
                ezcontentobject_tree.path_string, 
                ezcontentobject_tree.priority, 
                ezcontentobject_tree.remote_id, 
                ezcontentobject_tree.sort_field, 
                ezcontentobject_tree.sort_order, 
                ezcontentclass.serialized_name_list AS 
                class_serialized_name_list, 
                ezcontentclass.identifier           AS class_identifier, 
                ezcontentclass.is_container         AS is_container, 
                ezcontentobject_name.NAME, 
                ezcontentobject_name.real_translation, 
                a0.sort_key_int 
FROM   ezcontentobject_tree 
       INNER JOIN ezcontentobject 
               ON ( ezcontentobject_tree.contentobject_id = ezcontentobject.id ) 
       INNER JOIN ezcontentclass 
               ON ( ezcontentclass.version = 0 
                    AND ezcontentclass.id = ezcontentobject.contentclass_id ) 
       INNER JOIN ezcontentobject_name 
               ON ( ezcontentobject_tree.contentobject_id = 
                    ezcontentobject_name.contentobject_id 
                    AND ezcontentobject_tree.contentobject_version = 
                        ezcontentobject_name.content_version ) 
       INNER JOIN ezcontentobject_attribute a0 
               ON ( a0.contentobject_id = ezcontentobject.id 
                    AND a0.contentclassattribute_id = 747 
                    AND a0.version = ezcontentobject.current_version 
                    AND ( a0.language_id & ezcontentobject.language_mask > 0 
                          AND ( ( ezcontentobject.language_mask - ( 
                                        ezcontentobject.language_mask & 
                                        a0.language_id 
                                        ) ) & 1 ) + (( 
                              ( 
                              ezcontentobject.language_mask - ( 
                              ezcontentobject.language_mask & a0.language_id 
                                                              ) ) & 2 )) < 
                              ( a0.language_id & 1 ) + (( a0.language_id & 2 )) 
                        ) ) 
WHERE  ezcontentobject_tree.path_string LIKE '/1/2/60/63/%' 
       AND ezcontentobject_tree.node_id != 63 
       AND ezcontentobject_tree.node_id = ezcontentobject_tree.main_node_id 
       AND ezcontentobject.contentclass_id IN ( 17 ) 
       AND ( ezcontentobject_name.language_id & ezcontentobject.language_mask > 
             0 
             AND ( ( ezcontentobject.language_mask - ( 
                           ezcontentobject.language_mask & 
                           ezcontentobject_name.language_id 
                                                     ) 
                   ) & 
                       1 ) + (( ( ezcontentobject.language_mask - ( 
                                                 ezcontentobject.language_mask & 
ezcontentobject_name.language_id ) ) & 
2 ) 
) 
< 
( ezcontentobject_name.language_id & 1 ) + (( 
ezcontentobject_name.language_id & 2 )) ) 
AND ezcontentobject_tree.is_invisible = 0 
AND ezcontentobject.language_mask & 3 > 0 
ORDER  BY a0.sort_key_int DESC; 

ERROR 3065 (HY000): Expression #1 of ORDER BY clause is not in SELECT list, references column 'plein.a0.sort_key_int' which is not in SELECT list; this is incompatible with DISTINCT