正確使用計數

Question

我只想統計所有的子註釋以及統計所有屬於圖庫的圖像的所有喜歡。

SELECT Count(Message.id) AS subCount, 
     Count(likes.id), 
     Image.id, 
     Image.date_created, 
     Image.likes, 
     Image.path 
FROM images AS Image 
     LEFT JOIN messages AS Message 
       ON (Message.object_id = Image.id 
        AND Message.msg_type = 16) 
     LEFT JOIN likes AS Likes 
       ON (likes.object_id = Image.id 
        AND likes.object_type = 3) 
WHERE Image.gallery_id = 31 

當我使用計數，它只返回1行。有任何想法嗎？

Answer 1

你需要一個GROUP BY：

SELECT Count(Message.id) AS subCount, 
     Count(likes.id), 
     Image.id, 
     Image.date_created, 
     Image.likes, 
     Image.path 
FROM images AS Image 
     LEFT JOIN messages AS Message 
       ON (Message.object_id = Image.id 
        AND Message.msg_type = 16) 
     LEFT JOIN likes AS Likes 
       ON (likes.object_id = Image.id 
        AND likes.object_type = 3) 
WHERE Image.gallery_id = 31 
GROUP BY Image.id, 
      Image.date_created, 
      Image.likes, 
      Image.path