什麼是「額外」的意思是在這個Django的代碼

Question

TOPIC_COUNT_SQL = """ 
SELECT COUNT(*) 
FROM topics_topic 
WHERE 
    topics_topic.object_id = maps_map.id AND 
    topics_topic.content_type_id = %s 
""" 
MEMBER_COUNT_SQL = """ 
SELECT COUNT(*) 
FROM maps_map_members 
WHERE maps_map_members.map_id = maps_map.id 
""" 

maps = maps.extra(select=SortedDict([ 
    ('member_count', MEMBER_COUNT_SQL), 
    ('topic_count', TOPIC_COUNT_SQL), 
]), select_params=(content_type.id,)) 

我不知道這意味着，

感謝

Answer 1

這是一個method of QuerySet。