mysql - 我想使用 MySQl 将多个表结果计数合并为一个结果

Question

我想使用 MySql(查看所需的结果)将多个表的结果计数合并为一个结果，但如果您有任何疑问，我对此感到困惑或对此进行优化，请回答我或帮助我，我自己也尝试过使用 Union 进行此查询，但严重不成功(请参阅查询示例)

需要结果

post  post_comment_likes  post_comments  post_likes
2     0                   3              0

查询

SELECT COUNT(*) AS `post` FROM post WHERE user_id = "123456" UNION
SELECT COUNT(*) AS `post_comment_likes` FROM post_comment_likes WHERE user_id = "123456" UNION 
SELECT COUNT(*) AS `post_comments` FROM post_comments WHERE user_id = "123456" UNION
SELECT COUNT(*) AS `post_likes` FROM post_likes WHERE user_id = "123456" 

Answer 1

set @post = 0;
set @post_comment_likes = 0;
set @post_comments = 0;
Set @post_likes = 0;


 select count(*) into @post from .......;
 select count(*) into @post_comment_likes from ......;
 select count(*) into @post_comments from ......;
 select count(*) into @post_likes from ......;

select (@post + @post_comment_likes + @post_comments + @post_likes) ;

在上面的代码中，@post、@post_comment_likes、@post_comments、@post_likes 是 session 变量，您在它们前面加上'@'字符
使用上面的代码，您可以访问每个表的计数。