我对两列求和的基本操作有问题。它很简单,但不起作用。
我得到结果5 + 5 = 8,3 + 7 = 7
这是查询:
select
`wp_posts`.ID ,
(select count(*) from `co_likes`
where `wp_posts`.`ID` = `co_likes`.`id_post`
and `co_likes`.`deleted_at` is null) as `like_count`,
(select count(*) from `wp_comments`
where `wp_posts`.`ID` = `wp_comments`.`comment_post_ID`) as `comment_count` ,
(`comment_count`+`like_count`) as 'total_sum'
from
`wp_posts`
where
`post_type` in ('post', 'co_post')
and `post_status` = 'publish'
order by
(comment_count+like_count) desc;
这就是结果:
知道发生了什么?
答案 0 :(得分:2)
您不能在定义它们的同一select
(或where
)中使用列别名。在您的情况下,最好的可能是子查询:
select p.*, (`comment_count`+`like_count`) as total_sum
from (select `wp_posts`.ID ,
(select count(*) from `co_likes` where `wp_posts`.`ID` = `co_likes`.`id_post` and `co_likes`.`deleted_at` is null) as `like_count`,
(select count(*) from `wp_comments` where `wp_posts`.`ID` = `wp_comments`.`comment_post_ID`) as `comment_count` ,
from `wp_posts`
where `post_type` in ('post', 'co_post') and `post_status` = 'publish'
) p
order by total_sum desc;
如果您只想按总和订购,但不需要查看,可以将总和加到order by
:
select `wp_posts`.ID ,
(select count(*) from `co_likes` where `wp_posts`.`ID` = `co_likes`.`id_post` and `co_likes`.`deleted_at` is null) as `like_count`,
(select count(*) from `wp_comments` where `wp_posts`.`ID` = `wp_comments`.`comment_post_ID`) as `comment_count` ,
from `wp_posts`
where `post_type` in ('post', 'co_post') and `post_status` = 'publish'
order by (like_count + comment_count) desc