Question

我有桌子，我存储博客帖子的费率（喜欢，不喜欢），我需要为每个帖子选择好恶的数量（当然还有加入桌面的博客:)）表格如下：

+---------+---------+-----------+
| id_user |  rate   |  id_blog  |
+---------+---------+-----------+
|    1    |  like   |     1     |
|    2    | dislike |     1     |
|    3    |  like   |     1     |
|    6    |  like   |     1     |
               .    
               . 
               .

最好的方法是什么？或者像这样意识到它是个坏主意？

Answer 1

您可以使用：

SELECT 
  id_blog, 
  SUM(rate='like') AS like_count, 
  SUM(rate='dislike') AS dislike_count 
FROM 
  blog_posts 
GROUP BY 
  id_blog

选择值的计数

1 个答案: