Question

我试图计算评论最多的新闻。我有两个表：评论和包含相同列的新闻：News_ID。这是查询

select *,count(News_ID) as count from comments inner join news where comments.News_ID = news.News_ID group by comments.News_ID order by count DESC limit 4

我收到此错误

#1052 - Column 'News_ID' in field list is ambiguous

这是否意味着我想要计算的专栏？

Answer 1

确保您在选择中news_id或comments.news_id

说明您获得的news.news_id内容

select 
    *,
    count(comments.News_ID) as count 
from comments 
inner join news where comments.News_ID = news.News_ID 
group by comments.News_ID 
order by count DESC limit 4

Answer 2

您需要告诉您正在使用其列的表的名称，选择有两个News_ID列，因此在计数中它不明确，以便查询选择哪个表的列，也使用正确的语法进行连接with on clause

select n.*,c.*,count(n.News_ID) as count 
from comments c
inner join news n ON(c.News_ID = n.News_ID)
 group by c.News_ID 
order by count DESC limit 4

计算列时出错，内部连接另一个表

2 个答案: